http://www.eoearth.org/ Wed, 31 Dec 1969 19:00:00 GMT 15 en-us cutler@bu.edu http://www.eoearth.org/e/i/header_logo.gif http://www.eoearth.org/ http://www.eoearth.org/article/Diversification_in_agriculture <h1>Diversification explained<br /> </h1><p>Diversification of <a href="/article/Agriculture">agriculture</a> refers to the shift from the regional dominance of one crop to regional production of a number of crops, to meet ever increasing <a href="/article/Supply_and_demand">demand</a> for cereals, pulses, vegetables, fruits, oilseeds, fibres, fodder and <a href="/article/Grasses">grasses</a>, fuel, etc. It aims to improve <a href="/article/Soil">soil</a> health and a dynamic equilibrium of the agro-ecosystem. Crop diversification takes into account the economic returns from different value-added crops. It is different from the concept of multiple cropping or succession planting in which multiple crops are planted in succession over the course of a growing season. Moreover, it implies the use of environmental and human resources to grow a mix of crops with complementary marketing opportunities, and it implies a shifting of resources from low value crops to high value crops, usually intended for human consumption such as fresh market fruits and vegetables. With globalization of the <a href="/article/Market">market</a>, crop diversification in agriculture means to increase the total crop productivity in terms of quality, quantity and monetary value under specific, diverse agro-climatic situations world-wide. There are two approaches to crop diversification in agriculture. First is horizontal diversification, which is the primary approach to crop diversification in production agriculture. Here, diversification takes place through crop intensification by adding new high-value crops to existing cropping systems as a way to improve the overall productivity of a farm or region&#39;s farming economy. The second is the vertical diversification approach in which farmers and others add value to products through processing, regional branding, packaging, merchandising, or other efforts to enhance the product. Opportunities for crop diversification vary depending on risks, opportunities and the feasibility of proposed changes within a socio-economic and agro-economic context. Crop diversification may occur as a result of government policies. The &quot;Technology Mission on Oilseeds&quot;, &quot;Spices Development Board&quot;, &quot;Coconut Development Board&quot; etc. are examples where the Indian government created policies to thrust change upon farmers and the food supply chain at large as a way to promote crop diversity. Crop diversification is the outcome of several interactive effects of many factors:</p><ol><li>Environmental factors including irrigation, <a href="/article/Precipitation_and_fog">rainfall</a>, temperature, and <a href="/article/Soil">soil</a> fertility.</li><li>Technology-related factors including seeds, <a href="/article/Fertilizer">fertilizers</a> and water technologies, but also those related to marketing, harvest, storage, agro-processing, distribution, logistics, etc.</li><li>Household-related factors including regional food traditions, fodder and fuel as well as the labor and investment capacity of farm people and their communities.</li><li>Price-related factors including output and input prices as well as national and international  <a href="/article/Trade_and_the_environment">trade</a> policies and other economic policies that affect the prices either directly or indirectly.</li><li>Institutional and Infrastructure-related factors including farm size, location and tenancy arrangements, research, in-field technical support, marketing systems and government regulating policies, etc. <br /></li></ol><p>All these five factors are interrelated. The adoption of crop technologies is commonly assumed to be influenced primarily by resource-related factors when institutional and infrastructure factors can play as much or more of a role in their adoption. </p><strong> </strong> <p><a href='http://www.eoearth.org/article/Diversification_in_agriculture'>Read Full Article...</a></p> http://www.eoearth.org/article/Diversification_in_agriculture Tue, 17 Nov 2009 22:06:24 GMT http://www.eoearth.org/article/Australian_sea_lion <a href='http://www.eoearth.org/article/Australian_sea_lion'><img border='0' src='/upload/thumb/d/d8/Australian_Sea_Lion_1.jpg/260px-Australian_Sea_Lion_1.jpg' width='100'/></a> <p>Also known as the <strong>White-capped sea lion</strong>. The Australian sea lion (Scientific name: <em>Neophoca cinerea</em> (Péron, 1816) is one of 16 species of marine mammals in the family of <a href="/article/Eared_Seals">Eared seals</a> which include sea lions and fur seals. Together with the families of true seals and Walruses, Eared seals form the group of marine mammals known as Pinnipeds. </p><p>Eared seals differ from the true seals in having small external earflaps and hind flippers that can be turned to face forwards. Together with strong front flippers, this gives them extra mobility on land and an adult fur seal can move extremely fast across the beach if it has to. They also use their front flippers for swimming, whereas true seals use their hind flippers. </p><p>Australian sea lions are found on islands offshore of Australia, especially on Kangaroo Island and Dangerous Reef (near Port Lincoln) in southern Australia. The species is considered endangered and is protected.</p> <p><a href='http://www.eoearth.org/article/Australian_sea_lion'>Read Full Article...</a></p> http://www.eoearth.org/article/Australian_sea_lion Sat, 14 Nov 2009 20:04:01 GMT http://www.eoearth.org/article/Neophoca <a href='http://www.eoearth.org/article/Neophoca'><img border='0' src='/upload/thumb/d/d8/Australian_Sea_Lion_1.jpg/260px-Australian_Sea_Lion_1.jpg' width='100'/></a> <p><em>Neophoca</em> is a genus of just one species (a “monotypic” genus) within the <a href="/article/Eared_Seals">eared seal family</a> of sixteen species - the <a href="/article/Australian_sea_lion">Australian sea lion</a>. <a href="/article/Eared_Seals">Eared seals</a>  include sea lions and fur seals. Together with the families of true seals and Walruses, Eared seals form the group of marine mammals known as Pinnipeds. </p><p>Eared seals  differ from the true seals in having small external earflaps and hind flippers that can be turned to face forwards. Together with strong front flippers, this gives them extra mobility on land and an adult fur seal can move extremely fast across the beach if it has to. They also use their front flippers for swimming, whereas true seals use their hind flippers. </p><p>Australian sea lions are found on islands offshore of Australia, especially on Kangaroo Island and Dangerous Reef (near Port Lincoln) in southern Australia. The species is considered endangered and is protected.</p><p>For details see <a href="/article/Australian_sea_lion">Australian sea lion</a>.</p><p><strong>Further Reading</strong> </p><ol><li><a href="http://www.eol.org/pages/328616  " class='external text' title="http://www.eol.org/pages/328616  ">&lt;em&gt;Neophoca cinerea&lt;/em&gt; (Péron, 1816)</a> Encyclopedia of Life (accessed April 7, 2009)</li><li><a href="http://www.pinnipeds.org/species/auslion.htm" class='external text' title="http://www.pinnipeds.org/species/auslion.htm">Australian Sea Lions</a>, Seal Conservation Society (accessed April 7, 2009)</li><li>The Pinnipeds: Seals, Sea Lions, and Walruses, Marianne Riedman, University of California Press, 1991 <a href="http://www.amazon.com/dp/0520064984/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0520064984/?tag=encycofearth-20">ISBN: 0520064984</a> </li><li>Encyclopedia of Marine Mammals, Bernd Wursig, Academic Press, 2002 <a href="http://www.amazon.com/dp/0125513402/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0125513402/?tag=encycofearth-20">ISBN: 0125513402</a> </li><li>Marine Mammal Research: Conservation beyond Crisis, edited by John E. Reynolds III, William F. Perrin, Randall R. Reeves, Suzanne Montgomery and Timothy J. Ragen, Johns Hopkins University Press, 2005 <a href="http://www.amazon.com/dp/0801882559/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0801882559/?tag=encycofearth-20">ISBN: 0801882559</a> </li><li><span>Walker&#39;s Mammals of the World, </span><span>Ronald M. Nowak, </span><span>Johns Hopkins University Press, 1999 </span><a href="http://www.amazon.com/dp/0801857899/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0801857899/?tag=encycofearth-20">ISBN: 0801857899</a> </li><li><a href="http://marinebio.org/species.asp?id=267" class='external text' title="http://marinebio.org/species.asp?id=267">Australian Sea Lion</a>, MarineBio.org (accessed April 7, 2009) </li></ol> <p><a href='http://www.eoearth.org/article/Neophoca'>Read Full Article...</a></p> http://www.eoearth.org/article/Neophoca Sat, 14 Nov 2009 20:00:10 GMT http://www.eoearth.org/article/Cyclone_model <a href='http://www.eoearth.org/article/Cyclone_model'><img border='0' src='/media/approved/5/54/CM1.gif' width='100'/></a> <br /> <h1><span class="next">Reference</span></h1><ul><li> <a href="http://www.srh.noaa.gov/jetstream//synoptic/cyclone.htm" class='external text' title="http://www.srh.noaa.gov/jetstream//synoptic/cyclone.htm">Norwegian Cyclone Model</a></li></ul><p class="noprint">&nbsp;</p> <p><a href='http://www.eoearth.org/article/Cyclone_model'>Read Full Article...</a></p> http://www.eoearth.org/article/Cyclone_model Tue, 10 Nov 2009 11:06:31 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_8 <blockquote><p><em>In a world in which no biological ecosystem is free of human influence and no industrial ecosystem is free of biological influence, it is appropriate to abandon the artificial division between the two frameworks and develop a new synthesis—Earth system ecology—as the logical construct for all of Earth&#39;s ecosystems.</em> [14] <br />—Thomas Graedel <br /><br /><em>Cradle to grave designs dominate modern manufacturing.</em> [28: p. 27]<br />—architect Bill McDonough and chemist Michael Braungart <br /><br /><em>Energy analysis is the first step to determine and compare energy consumption and production of different options. This can involve complex life-cycle net energy analysis, but often the most useful energy analysis is done by calculating simple energy consumption or conversion efficiency on the back of an envelope. </em>[34: p. 166]<br />—John Randolph and Gilbert Masters, 2008 </p></blockquote><p>The <a href="/article/Energy_return_on_investment_%28EROI%29">energy return on investment (EROI)</a> value is a ratio and therefore has no specific dimension. When we use the EROI, we have to decide whether by-products (or coproducts) of the energy conversion process belong on the top or the bottom of the fraction. In the case of some energy systems, for example, ethanol production, the EROI result will be very different, depending on whether we consider the coproduced energy as a positive output—to be added to the numerator, on top, because it can be used “as is” without further conversion and it increases energy return—or a negative input—to be added in the denominator because it needs to be disposed of at some added energy cost and it shrinks energy return. In these cases, an alternative is to compute the net energy value in a system. For example, the production of ethanol creates not only liquid ethanol fuel but also usable animal feed and solid fuel that have energy value too. The total value of the net energy gain or loss in a system can be calculated as follows, which lets us avoid choosing whether a by-product is a gain or loss: </p><blockquote><p><strong>Equation 4</strong>: Net energy value (NEV) = Energy output - Energy input = (Energy in liquid ethanol + Feed by-product + Solid fuel by-product) - (Energy needed to product ethanol) </p></blockquote><p>Net energy computes as an absolute value with a specific dimension, such as Btu per gallon (Btu/gal) in the case of ethanol or gasoline. One British thermal unit (Btu) is small unit of energy equal to 0.293 Watt-hours.</p><p>Notice the simple EROI expression did not have a time component. Very often we also want to examine the time value of energy conversions, that is, their break-even or payback period. For example, how much time will it take an energy system, such as a new geothermal system, a wind farm,a solar array, or even a new more-efficient oil burner, to recover its start-up costs? This is especially useful for systems that have one-time development costs and very low net operating costs, like wind or <a href="/article/Photovoltaics">photovoltaic</a> or solar thermal installations. For such systems, the energy payback time (EPBT) is the equivalent of the inverse of the energy return on investment value (1/EROI). All we need to do is add the time component—typically years—to the denominator on the bottom of the fraction: </p><blockquote><p><strong>Equation 5</strong>: Energy payback time (EPBT) = (Energy input of up-front one-time costs)/(Energy output) = Btu/(Btus per year) </p></blockquote><p>where energy input is the up-front indirect energy cost of creating a system, which is divided by the energy output, which is usually written as the useful energy (or power) output per unit of time, for example, Btu/year. </p><p>For example, in the realm of photovoltaic technologies, the EPBT approach helps us compare the payback time for two different kinds of solar electric panels if we know the indirect up-front “embodied” energy costs of producing the system. The energy input for a crystalline silicon PV module is 5,600 kilowatt-hours per peak kilowatt-hour power output of the module, and for thin-film copper indium diselenide (CIS) modules the energy input is 3,100 (in the same units). So the new CIS module takes less energy to produce. Given that the Sun’s energy shining on two panels is going to be the same, 1,700 (in the same units), we can see that the thin-film module has a payback of 1.8 years versus 3.3 years for the silicon-based module. In reality, the actual net power performance of the panels is about 80% of the original because of system losses to the power after it leaves the module (line loss, inverter operations, etc.). So the energy payback times become 2.2 years for the thin-film and 4.1 years for the silicon modules. </p><p>Now, here is the interesting part. Both these technologies have an expected life of 30 years. So now we can compute the energy return on energy investment as follows, and learn that the newer thin-film module will have an EROI twice as high as the older silicon technology:</p><blockquote><strong>Equation 6</strong>: <br /><blockquote>EROI_silicon = 30 years/4.1 years = 7<br />EROI_{thin-film CIS} = 30 years/2.2years = 14<br /></blockquote></blockquote><p>Table 8.5 shows some current EROI values. Note the huge drop in energy return on US gas and oil production over the seven-decade time. Note also that the energy return on thin-film photovoltaic modules is only slightly lower that on nuclear power—without taking any of the actual economic costs of each into account. </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_8'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_8 Tue, 10 Nov 2009 08:17:52 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_7 <a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_7'><img border='0' src='/upload/thumb/a/a6/F07.01_EnergyFlow_USEIA_AER_2008_038407.jpg/280px-F07.01_EnergyFlow_USEIA_AER_2008_038407.jpg' width='100'/></a> <blockquote><em>Global climate change … time and geographic scales are unprecedented in their scope, touching every human activity that involves energy or land and requiring a strategy that stretches a century or more into the future. The actions needed to manage the risks of climate change require long-term commitments to severely limit net emissions of greenhouse gases to the atmosphere by developing and deploying new ways of producing and using energy across the world. </em>[4] <br />—Jae Edmonds, Global Energy Technology Strategy Program, 2007 <br /><br /><em>Utilities made their money by building stuff ... because they were rewarded by their regulators with increased rates on the basis of those capital expenses. The more capital they deployed, the more they made.… We are not going to regulate our way out of the problems of the Energy-Climate Era. We can only innovate our way. </em>[6: pp. 222, 243] <br />—Thomas Friedman, 2008 <br /></blockquote><p>As much as we love cars, the typical car is not an efficient transportation device, for two big reasons: An internal combustion engine converts much of the fuel energy to waste <a href="/article/Heat">heat</a>, and most cars are far heavier than they need to be. There are many ways to measure efficiency. For example, we could use the ratio of the object being moved to the object doing the moving. Americans use 680 kilograms (1,500 pounds) of metal and plastic in the form of an average passenger car to transport an average adult who weighs 68 kilograms (150 pounds). So the “efficiency” of the automobile cannot exceed 10%—the fraction of the car’s total mass represented by the passenger (150 divided by 1,500). But this calculation is misleading. The mass of a car affects efficiency only indirectly, by increasing friction and conversion of energy to heat during braking, especially in stop-and-go traffic. Hybrids in which this energy is recaptured lose less energy to heat. Shedding vehicle weight would make gas mileage go up, even without changing the engine itself, as a lower weight reduces friction. </p><p>The efficiency of a typical car is limited through the underlying physics of burning hydrocarbons. Internal combustion engines are not efficient in their conversion of the chemical energy in gas or diesel fuel to mechanical energy for the drivetrain. The “fuel-to-wheel” efficiency for automobiles is about 20%. [18] Only about one-fifth of the chemical energy in a gasoline tank actually reaches the drivetrain as mechanical energy to move the vehicle. All the rest—about 80%—of the energy in your gas tank is used for something else other than driving. Where does the energy go? The “lost” energy escapes as <a href="/article/Evaporation">evaporation</a>, waste heat, internal friction, and exhaust gas. </p><p>A typical car traveling at 65 kilometers (40 miles) per hour on a level road consumes 7.6 liters per hour (2 gallons), which represents about 72 kilowatts (kW) of chemical energy. In the combustion process of a gasoline engine, four-fifths (57 kW) of the original chemical energy is lost as heat. The engine converts the remaining energy (about 14 kW) in the gasoline into the mechanical energy to drive the lights, fan, generator, water pump, transmission, and drive train. These components shed almost one-third of mechanical energy as heat (about 5 kW). Of the remaining mechanical energy, about half is expended as air friction and half goes into actually turning the tires on a road via friction. Only about 10 of the original 72 kW are available for forward (or backward) motion. In short, the thermodynamic efficiency of using internal combustion engines in our cars represents an actual energy efficiency of just under 14%. [16] </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_7'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_7 Tue, 10 Nov 2009 08:16:44 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_6 <p>(or Live Where You Work and Shop Where You Play: Dead Malls and Smart Growth) </p><blockquote><p><em>Messages about the seriousness of global warming have a poor track record of producing measurable behavioral change by themselves. [7]</em></p><p>—Gerald Gardner and Paul Stern, 2008 </p><p><em>The carbon Footprint measures the demand on biocapacity that results from burning fossil fuels in terms of the amount of forest area required to sequester these carbon dioxide emissions. Note that this does not suggest planting forests is the “solution” to climate change; on the contrary, it shows that the biosphere does not have sufficient capacity to sequester all the carbon we are currently emitting. [18]</em></p><p>—Mathis Wackernagel, Global Footprint Network </p></blockquote><p>More Americans now live in suburbs than in cities or in rural settings. We are wedded to our cars. Type smart growth into your Web browser search engine, and you will find thousands of uses of the phrase. What does it really mean? At its simplest, smart growth is the development of living, shopping, and work environments that are as efficient with natural resources as possible and as healthy for residents as possible. In addition to efficiency and health benefits, a third asset of smart growth is financial. Such development often produces economic returns as high as or higher than more resource-intense, older development patterns. The economic benefits derive from lower transit costs, higher use per parcel, and more dollars kept circulating locally.</p><p>Smart growth is also known as “location efficient development,” “the New Urbanism,” “the New Localism,” or “transit oriented development.”  Kaid Benfield, director of NRDC’s Smart Growth Program, writes a very informative blog column in which he shows that such highly efficient and healthier development can be undertaken in rural hamlets, like Starksboro, Vermont, as well as in traditional suburbs, like Glenview, Illinois, or within neighborhoods in some of our largest cities, like the Project Row Houses of Houston, Texas. [1]</p><p>As we reorganize our communities so we drive less, walk more, live closer to conveniences, and retain open space for recreation, the sprawling shopping mall may be nearing the end of its life. Clusters of stores surrounded by acres of parked cars dominate the suburban landscape now. But abandoned “dead malls” number in the hundreds, if not thousands, as communities change.  Many mall owners and developers are undertaking a retrofit of existing single-use shopping centers. They are bringing mixed-use buildings to the area, in which housing, transportation, and office space are commingled with retail spaces. Live where you work, and shop where you play.</p><p>The United States Green Building Council (USGBC) is collaborating with NRDC and the Congress for the New Urbanism to extend green practices from individual buildings to entire neighborhoods. The USGBC is the driving force behind the LEED rating standards for green buildings. But unless the communities in which such buildings are located are also redesigned, the benefits will not be maximized. [5] The new initiative, called the LEED for Neighborhood Development Rating System, is under development. </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_6'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_6 Tue, 10 Nov 2009 08:13:44 GMT http://www.eoearth.org/article/Sea_water <a href='http://www.eoearth.org/article/Sea_water'><img border='0' src='/media/approved/8/83/Sea_water1_NOAA.jpg' width='100'/></a> <p> If there is one thing that just about everyone knows about the <a href="/article/Ocean">ocean</a> is that it is salty. The two most common elements in sea water, after <a href="/article/Oxygen">oxygen</a> and <a href="/article/Hydrogen">hydrogen</a>, are sodium and chloride. Sodium and chloride combine to form what we know as table salt.</p> <p>Sea water salinity is expressed as a ratio of salt (in grams) to liter of water. In sea water there is typically close to 35 grams of dissolved salts in each liter. It is written as 35‰. The normal range of ocean salinity ranges between 33-37 grams per liter (33‰ - 37‰).</p> <p>But as in weather, where there are areas of high and low pressure, there are areas of high and low salinity. Of the five ocean basins, the Atlantic Ocean is the saltiest. On average, there is a distinct decrease of salinity near the equator and at both poles, although for different reasons.</p> <p>Near the equator, the tropics receive the most rain on a consistent basis. As a result, the fresh water falling into the ocean helps decrease the salinity of the surface water in that region. As one move toward the poles, the region of rain decreases and with less rain and more sunshine, evaporation increases.</p> <p>Fresh water, in the form of water vapor, moves from the ocean to the atmosphere through evaporation causing the higher salinity. Toward the poles, fresh water from melting ice decreases the surface salinity once again.</p> <p>The saltiest locations in the ocean are the regions where evaporation is highest or in large bodies of water where there is no outlet into the ocean. The saltiest ocean water is in the Red Sea and in the Persian Gulf region (around 40‰) due to very high evaporation and little fresh water inflow.</p> <p><a href='http://www.eoearth.org/article/Sea_water'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_water Sun, 01 Nov 2009 22:51:51 GMT http://www.eoearth.org/article/Layers_of_the_ocean <a href='http://www.eoearth.org/article/Layers_of_the_ocean'><img border='0' src='/upload/thumb/7/75/Ocean_layers.jpg/400px-Ocean_layers.jpg' width='100'/></a> <p> Just as the atmosphere is divided into layers the <a href="/article/Ocean">ocean</a> consists of several layers itself. </p> <p><a href='http://www.eoearth.org/article/Layers_of_the_ocean'>Read Full Article...</a></p> http://www.eoearth.org/article/Layers_of_the_ocean Sun, 01 Nov 2009 22:32:57 GMT http://www.eoearth.org/article/Rip_current <a href='http://www.eoearth.org/article/Rip_current'><img border='0' src='/upload/thumb/1/1c/RipCurrents1.jpg/300px-RipCurrents1.jpg' width='100'/></a> <p> Rip currents are powerful, channeled currents of water flowing away from shore. They typically extend from the shoreline, through the surf zone, and past the line of breaking waves. Rip currents can occur at any beach with breaking waves, including the Great Lakes.</p> <p>Rip currents most typically form at low spots or breaks in sandbars, and also near structures such as groins, jetties and piers. Rip currents can be very narrow or extend in widths to hundreds of yards. The seaward pull of rip currents varies: sometimes the rip current ends just beyond the line of breaking waves, but sometimes rip currents continue to push hundreds of yards offshore.</p> <p>Rip currents form as incoming waves create an underwater sandbar close to shore (#1 above), and the waves push more and more water in between the sandbar and the shore (#2) until a section of this sandbar collapses and the water rushes back toward the sea (#3) through a narrow gap. Once the flowing water pass through the narrow gap it begins to spread out (#4). It is here where the velocity and strength of the rip current circulation begins to weaken considerably.</p> <p>Rip currents can be killers as they are the leading surf hazard for all beachgoers. They are particularly dangerous for weak or non-swimmers. Rip current speeds are typically 1-2 feet per second. However, speeds as high as 8 feet per second have been measured which is faster than an Olympic swimmer can sprint!</p> <p> The United States Lifesaving Association estimates that the annual number of deaths due to rip currents on our nation&#39;s beaches exceeds 100. Rip currents account for over 80% of rescues performed by surf beach lifeguards.</p> <p>The drowning deaths occur when people, pulled offshore, are unable to keep themselves afloat and swim to shore. This may be due to any combination of fear, panic, exhaustion, or lack of swimming skills.</p> <h2 class="leftalign">Dispelling the Myth of the Rip</h2> <p>A rip current is a horizontal motion not a vertical motion. Rip currents <strong>do not</strong> pull people under the water; they pull people away from shore. The rip current is typically the strongest about a foot off of the bottom, which can cause your feet to be knocked out from under you making it feel like something under the water was pulling you. This is where the incorrect term &quot;undertow&quot; comes from.</p> <p>Also, another incorrect term used for rip currents is the &quot;rip tide&quot;. Rip currents would exist with or without tides. However, low tide can enhance the intensity of the current.</p> <p><a href='http://www.eoearth.org/article/Rip_current'>Read Full Article...</a></p> http://www.eoearth.org/article/Rip_current Sun, 01 Nov 2009 21:06:22 GMT http://www.eoearth.org/article/Weather_and_oceans <a href='http://www.eoearth.org/article/Weather_and_oceans'><img border='0' src='/media/approved/6/61/Oceans-World_NOAA.jpg' width='100'/></a> <h1>Weather and oceans <br /></h1> <p>One cannot learn about the weather we experience without considering the ocean and its effect on our weather...and the weather&#39;s effect on it. We must consider the ocean because nearly 71% of the earth&#39;s surface is covered by it and more than 97% of all our water is contained in it.</p> <p>We must consider the ocean and its impact as more than one-half of the world&#39;s population lives within 60 miles (100 kilometers) of the ocean.</p> <p>We must consider the ocean as its ability absorb, store, and release heat into the atmosphere is huge and often directly affects us. In fact, just the top 10 feet of the ocean surface contains more heat than our entire atmosphere.</p> <p>Major climate events, such as <a href="/article/El_Ni%C3%B1o%2C_La_Ni%C3%B1a_and_the_southern_oscillation">El Niño</a>, result from ocean temperature changes. These temperature changes then have impacts on weather events such as hurricanes, typhoons, floods and droughts which, in turn, affect the prices of fruits, vegetables and grains.</p> <p>It is essential that we consider &quot;the ocean&quot;.</p> <p><a href='http://www.eoearth.org/article/Weather_and_oceans'>Read Full Article...</a></p> http://www.eoearth.org/article/Weather_and_oceans Sun, 01 Nov 2009 20:48:17 GMT http://www.eoearth.org/article/Umbrella_species <p>The concept of an umbrella species has been used by conservation practitioners to provide protection for other species using the same habitat as the umbrella species.  As the term implies, a species casts an “umbrella” over the other species by being more or equally sensitive to habitat changes. Thus monitoring this one species and managing for its continued success results in the maintenance of high quality habitat for the other species in the area.  Animals identified as umbrella species typically have large home ranges that cover multiple habitat types.  Therefore, protecting the umbrella species effectively protects many habitat types and the many species that depend on those habitats. Although the effectiveness of this conservation approach is debated, it is often used by practitioners to select a minimum size for protected areas.</p> <p><a href='http://www.eoearth.org/article/Umbrella_species'>Read Full Article...</a></p> http://www.eoearth.org/article/Umbrella_species Thu, 29 Oct 2009 21:38:45 GMT http://www.eoearth.org/article/Shifting_mosaic_steady-state <a href='http://www.eoearth.org/article/Shifting_mosaic_steady-state'><img border='0' src='/upload/thumb/7/7f/SMSS.jpg/350px-SMSS.jpg' width='100'/></a> <p>&nbsp;</p> <p><a href='http://www.eoearth.org/article/Shifting_mosaic_steady-state'>Read Full Article...</a></p> http://www.eoearth.org/article/Shifting_mosaic_steady-state Thu, 29 Oct 2009 21:31:14 GMT http://www.eoearth.org/article/Climate_Solutions_Consensus <a href='http://www.eoearth.org/article/Climate_Solutions_Consensus'><img border='0' src='/media/approved/9/93/Cover_1951_blocksteincoverfrontr02pa.jpg' width='100'/></a> </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions_Consensus'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions_Consensus Thu, 29 Oct 2009 20:58:01 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_4 <a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_4'><img border='0' src='/upload/thumb/7/79/F04.01_IPCC_WG1_faq-5-1-fig-1.jpg/280px-F04.01_IPCC_WG1_faq-5-1-fig-1.jpg' width='100'/></a> <blockquote><p><em>As seawater warms up, it expands, increasing the volume of the global ocean</em>. [28]</p><p>—Gerald Meehl and his IPCC colleagues, 2007 </p></blockquote><blockquote><p><em>Global warming raises the potential of unlocking large amounts of fresh water now frozen in the vast Greenland ice sheet and in Arctic Ocean sea ice. Warming air temperatures could also increase evaporation in low latitudes and transport freshwater vapor toward high latitudes, where it falls as rain or snow into the oceans. Could these factors tip the freshwater balance in the North Atlantic in the future?</em> [27]</p><p>—Jerry McManus and Delia Oppo, Woods Hole Oceanographic Institution, 2006 </p></blockquote><p>As we have learned, the <a href="/article/Ocean">ocean</a> is a vast reservoir, not only of water, but also of heat. The thermal layers are not uniform. Surface water warmed by the sun tends to contain more heat than layers 100 meters below the surface or deeper. The bigger the <a href="/article/Temperature">temperature</a> difference between the warmer top water and colder bottom water, the more potential exists to convert that difference into other kinds of energy, such as electricity. Ocean Thermal Energy Conversion (OTEC) is an energy technology that converts <a href="/article/Solar_radiation">solar radiation</a> to electric power.  OTEC systems use the ocean&#39;s natural thermal gradient—the difference in temperatures of the ocean&#39;s layers of water—to drive a power-producing cycle. As long as the temperature between the warm surface water and the cold deep water differs by about 20°C (36°F), an OTEC system can produce a significant amount of power, with little impact on the surrounding environment. As the OTEC Web site notes, “The oceans are thus a vast renewable resource, with the potential to help us produce billions of <a href="/article/Watt">watts</a> of electric power.” [31] According to some experts, this potential may be as large as 10,000 billion watts of continuous baseload power generation. </p><p>Essentially, the technology involves pumping cold deep ocean water to the surface, exchanging the thermal energy between the two reservoirs in a heat engine, and returning the water to the mixed layer between the warm top and cold deep layers. Experimental OTEC stations have been in operation since the late 1990s. The by-products of the heat exchange include clean <a href="/article/Freshwater">freshwater</a> (which rivals in quality that of modern desalination plants) and cold &quot;waste&quot; water, which could be used for marine aquaculture or even for growing plants on land, as the Seawater Greenhouse project shows.*</p><p>*www.seawatergreenhouse.com </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_4'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_4 Thu, 29 Oct 2009 20:57:20 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_3 <a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_3'><img border='0' src='/upload/thumb/4/4e/F03.01_ad-AR4-WGI_CO2-Rate_20kya.jpg/280px-F03.01_ad-AR4-WGI_CO2-Rate_20kya.jpg' width='100'/></a> <blockquote><p><em>A large fraction of fossil fuel CO₂emissions stays in the air a long time, one-quarter remaining airborne for several centuries.... Thus moderate delay of fossil fuel use will not appreciably reduce long-term human-made climate change. Preservation of a climate resembling that to which humanity is accustomed ... requires that most remaining fossil fuel carbon is never emitted to the atmosphere. [8]</em></p><p>—James Hansen and colleagues, 2008 </p></blockquote><p>Anyone who has traveled to the “Mile High City,” as Denver, Colorado, is known, will attest: The air is thinner in the Rocky Mountains at 1,600 meters (1 mile) above sea level than in New York City, which is at sea level. The <a href="/article/Atmospheric_composition">atmosphere</a> is thickest at sea level and decreases exponentially in density and <a href="/article/Pressure">pressure</a> with elevation. Starting at sea level, we have a layer about 18 kilometers (km) thick, called the troposphere. Almost all human activity, from mountain climbing to flying in jet airplanes, takes place in the troposhere. The air in the troposphere is constantly circulating. (Tropos means “turning” in Greek.)</p><p>The Earth bakes the air from the bottom by radiating some <a href="/article/Heat">heat</a> from the Sun back into the sky. Air in the troposphere rises, expands, and cools. If the air contains moisture, the moisture may condense to form clouds of rain droplets or ice crystals. Clouds form in the troposphere. Water within the bottom 4 km of the troposphere will not freeze. Water arriving in the top 4 km can form ice. And in between, either ice or rain can form. Ninety percent of all Earth’s air lies within about 16 km (10 miles) of the Earth’s surface. At the top of the troposphere, the air is quite cold, about -55°C (-67°F). </p><p>Above the troposphere lies the stratosphere for another 30 km or so. Within the stratosphere sits a layer of large <a href="/article/Oxygen">oxygen</a> molecules, <a href="/article/Ozone">ozone</a> (O₃), that block harmful <a href="/article/Solar_radiation">solar radiation</a> from reaching us. Without this “good ozone,” the oceans would evaporate and life would cease. The air in the stratosphere is relatively stable. It does not mix with the air below it. Interestingly, air at the top of the stratosphere is warmer—about 0°C (32°F)—than the air in the troposphere just below it. The ozone layer’s absorbing solar radiation causes this warmth. </p><p>The less dense mesosphere lies above the stratosphere and is considerably colder, about -85°C (-121°F) at its top. At about 80 km above sea level, the thermosphere begins above the mesosphere. The thermosphere is the least dense zone; it contains very little gas and gradually warms to about -50°C (-58°F) because the Sun is effectively baking it from above. At about 90 km above sea level, the <a href="/article/Atmospheric_composition">atmosphere</a> gradually thins until there are no air molecules left and interplanetary space begins. Both the mesosphere and thermosphere are so far removed from the Earth and have so little gas that they are scarcely affected by the processes that cause warming or cooling in the lower troposphere or stratosphere. The lower two zones of the atmosphere—the troposphere and the stratosphere—are more sensitive to <a href="/article/Temperature">temperature</a> drivers such as <a href="/article/Greenhouse_gas">greenhouse gases</a>, and these are where we will focus our attention.</p><p>So what causes the Earth to warm or cool? The short answer is that many different processes contribute to warming or cooling of the Earth’s lower atmosphere and surface. For millions of years, three naturally occurring factors caused variation in the Earth’s average surface temperature: the Sun, volcanic eruptions, and the Earth’s orbit. </p><p>Our Sun is a star containing a thermonuclear furnace that ejects heat as radiation. Over time, very small but detectable variations occur in the output of heat from the Sun. Sunspots and their related solar flares and are examples. Slightly more or less heat arriving from the Sun will cause a rise or fall in the heat that reaches the Earth’s surface. Sunspots appear to come and go in 10-year cycles and cannot alone explain the rise in temperature we have observed since the <a href="/article/Industrial_Revolution">industrial age began</a>. </p><p><a href="/article/Volcano">Volcanoes</a> modify the <a href="/article/Atmospheric_composition">atmosphere</a> whenever they erupt. Explosive volcanic activity injects <a href="/article/Aerosols">aerosol</a> particles of soot high into the stratosphere where they form clouds that might cool the Earth. Such particle-laden clouds may prevent heat from the Sun from reaching the Earth’s surface and thereby cause a temporary cooling, However, volcanic eruptions also emit water vapor, <a href="/article/Carbon_dioxide">carbon dioxide</a>, and other gases that can have long-term warming effects. In the past century, four major volcanic eruptions have each caused a short-term drop in the Earth’s average temperature.  Volcanic activity has actually been fairly uncommon in the past 250 years, so it is not an adequate explanation for the sudden rise of carbon dioxide in the atmosphere.  </p><p>Finally, the geometry of Earth’s orbit is not a uniform ellipse. Much as a spinning top may change the tilt of its axis while its axis gradually traces a conical path, the Earth’s orbit does wobble a bit over a very long period of time. This orbital eccentricity and slight variations in axis angles occur over very long time scales of ten of thousands of years. The Earth’s orbital fluctuation or axis tilt has not changed measurably in the past thousand years or more. So planetary geometry cannot explain the sudden rise in carbon dioxide since 1850, when the industrial era began. </p><p>Other smaller natural factors that affect how much <a href="/article/Carbon_dioxide">carbon dioxide</a> concentrates in the <a href="/article/Atmospheric_composition">atmosphere</a> over the long term include the number of marine organisms (which we will discuss in Chapter 4) available to extract carbon dioxide to make shells, and the abundance of mountain ranges that remove carbon dioxide through chemical weathering. But the number of mountain ranges with exposed rock has not changed appreciably in the past 150 years. So the latter does not contribute to the explanation of the rise in atmospheric carbon dioxide. We will learn in Chapter 4 why marine organisms do play a vital role, but not in a way that contributed to the already observed increase in carbon dioxide. </p><p>If all of the above processes could cause the Earth to warm up, what could cause the Earth to cool down? We saw earlier how volcanic clouds have a temporary cooling effect until they are dispersed. Three naturally occurring processes could cool the Earth over the long term and have done so in the past. </p><p>The first is the albedo effect that happens with good snow cover. When snow or ice forms and remains on the surface, it reflects most of the <a href="/article/Solar_radiation">solar radiation</a> that hits it, bouncing radiated heat back into the atmosphere and out into space. It is the <a href="/article/Albedo">albedo</a> effect that gives snow skiers a deep tan because they get sun from above and reflected from below. Soil or water would have absorbed the heat and warmed up much more than the pale ice or snow cover. More snow or ice cover leads to more albedo and more cooling and therefore more snow and ice. The albedo effect is a positive feedback loop because its effect intensifies the process that causes it. </p><p>The second process is the <a href="/article/Ocean">ocean</a>’s action as a heat conveyor. The ocean is a giant heat engine. As climates cools down, the <a href="/article/Evaporation">evaporation</a> of <a href="/article/Seawater">seawater</a> slows down. Warmer air temperature causes surface ocean water to evaporate, causing a higher salt-to-water ratio and subsequently surface waters that are denser but warmer than the layers below. The deep-sea sinking of water requires dense, salty water. This sinking drives currents such as the Gulf Stream, which moves warm surface water to the North <a href="/article/Atlantic_Ocean">Atlantic</a> and cold deep water from the North Atlantic toward the equator. Any change in the sinking of the cold northern water will alter the Gulf Stream and, with it, northern Europe’s climate, currently warmed by it. Any cooling in northern Europe might alter the albedo effect of snow cover. So these are all interconnected. </p><p>Third, the biological processes that change <a href="/article/Carbon_dioxide">CO₂</a> concentrations could also contribute to cooling the Earth. While biological processes may not initiate climate changes, they may amplify changes underway by altering the composition of the atmosphere in small but significant ways. For example, if more <a href="/article/Plankton">plankton</a> grew in the <a href="/article/Ocean">oceans</a>, their <a href="/article/Photosynthesis">photosynthesis</a> and shell-making process would take up and store more carbon, removing it from the <a href="/article/Atmospheric_composition">atmosphere</a> during the life cycle of the plankton. Biological processes, such as <a href="/article/Forest_biome">forest</a> growth, are carbon stores but not necessarily long-term carbon sinks.  Biological processes alone cannot explain the sudden rise in modern atmospheric <a href="/article/Carbon_dioxide">carbon dioxide</a>. Lowering the carbon dioxide in the atmosphere would reduce the <a href="/article/Greenhouse_effect">greenhouse effect</a> and lower temperatures. We will discuss plankton more in Chapter 4. </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_3'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_3 Thu, 29 Oct 2009 20:56:39 GMT http://www.eoearth.org/article/Editorial_Board <a href='http://www.eoearth.org/article/Editorial_Board'><img border='0' src='/upload/thumb/5/5d/Cutler_bio_image.jpg/100px-Cutler_bio_image.jpg' width='100'/></a> <?php $page_title = "Editorial Board";?> <?php include($_SERVER['DOCUMENT_ROOT'] . '/e/template/header.php');?> <p><a href='http://www.eoearth.org/article/Editorial_Board'>Read Full Article...</a></p> http://www.eoearth.org/article/Editorial_Board Wed, 28 Oct 2009 17:51:18 GMT http://www.eoearth.org/article/Natural_Community <p>A natural community is an interactive assemblage of organisms, their physical environment, and the natural processes that affect them. Environmental factors such as <a href="/article/Soil">soil</a> type, bedrock type, moisture level, slope, slope aspect, climate, and the <a href="/article/Natural_disturbance_regime">natural disturbance regime</a> play a key role in determining a species&#39; ability to survive there. The organisms within a natural community include: plants, animals, fungus, and microorganisms. Natural communities occur in patterns throughout the earth and range in size from thousands of acres, such as a Northern Hardwood Forest, to less than one acre, such as a seep. Natural communities change over geological and evolutionary time, and are not static.</p><p>Natural communities classification is used as a management tool. By grouping complex systems into categories, people are able to process information about those systems which may otherwise prove difficult. <a href="/article/Ecology">Ecologists</a> categorize complex natural systems to better understand spatial patterns in nature. </p> <p><a href='http://www.eoearth.org/article/Natural_Community'>Read Full Article...</a></p> http://www.eoearth.org/article/Natural_Community Wed, 28 Oct 2009 09:51:07 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_5 <a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_5'><img border='0' src='/upload/thumb/8/82/F05.02a_USGS_2008_Invasives_FL-nas.er.usgs.gov-grap-3.jpg/280px-F05.02a_USGS_2008_Invasives_FL-nas.er.usgs.gov-grap-3.jpg' width='100'/></a> <h1>Case Study of Chesapeake Bay Eel grass<br /></h1><blockquote><p><em>Over the past 50 years, humans have changed ecosystems more rapidly and extensively than in any comparable period in human history, largely to meet fast-growing demands for food, fresh water, timber, fiber, and fuel. </em></p><p>—Millennium Ecosystem Assessment 2005</p><p><em>The threats to the future of biodiversity include habitat conversion, environmental toxification, climate change, and direct exploitation of wildlife. [15] </em></p><p>—Paul Ehrlich and Robert Pringle, 2008 </p><p><em>Species are becoming extinct at the fastest rate known in geological history and most of these extinctions have been tied to human activity. [18]</em></p><p>—Ecological Society of America, 2008 </p></blockquote><p>The loss of critical <a href="/article/Biodiversity">biodiversity</a> is just as threatening for aquatic environments as land-based life. For example, eelgrass is common throughout the world in coastal <a href="/article/Estuary">estuaries</a>. There it serves as a primary producer of <a href="/article/Oxygen">oxygen</a> through <a href="/article/Photosynthesis">photosynthesis</a>. “Aquatic grasses, or submerged aquatic vegetation, are one of the most important habitats in Chesapeake Bay. Bay grasses provide critical habitat to key species such as blue crab and striped bass, and can improve water clarity.”  [5]  </p><p>The Chesapeake Bay is the largest estuary in the United States, where <a href="/article/Freshwater">fresh</a> and salt water mix on daily tides in a life-sustaining broth for myriad plants and animals. The bay’s <a href="/article/Watershed">watershed</a> is fed by 150 <a href="/article/River">rivers</a> from six states and the District of Columbia. The bay itself is 300 km (200 miles) long. In the 1970s, the bay contained one of the planet&#39;s first identified <a href="/article/Eutrophication">marine dead zones</a>, an area with too little oxygen to support life. Farm runoff and industrial waste prevented <a href="/article/Solar_radiation">sunlight</a> from reaching the bottom of the bay, and the eelgrass beds withered. While the environmental regulations have largely helped clean up the worst <a href="/article/Point_source_pollution">pollution sources</a>, the bay has continued to suffer dramatic losses of the nursery beds. In 2005, 78,000 acres of eelgrass beds remained. The very next year, 2006, a 25% decline caused the eelgrass beds to shrink to just under 60,000 acres. The result is a greatly impoverished estuary whose oxygen-starved waters can no longer support the marine life for which it was once so famous. Delicious Maryland crab cakes may be a thing of the past in a very short time. </p><p>{Insert Figure 5.10 Aquatic Grass Collapse in Chesapeake Bay}</p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_5'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_5 Tue, 27 Oct 2009 22:47:32 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_2 <a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_2'><img border='0' src='/upload/thumb/0/0f/F02.03_ar4-wg1-technical-summary-boxTS.5.jpg/320px-F02.03_ar4-wg1-technical-summary-boxTS.5.jpg' width='100'/></a> <p>In 2003 Michael Mann and Philip Jones examined <a href="/article/Temperature">temperatures</a> for the past 2,000 years in a research paper that brought together many prior temperature records. The 2003 Mann and Jones study gathered temperature data for 13 different regions based on more than 23 different proxy records. In other words, they wanted to know whether all these different data sets revealed the same underlying trends. They concluded the best available data did indicate the globe’s average surface temperature has been getting higher in the past 2,000 years. But the excellent Mann and Jones compilation is a smaller-scale model of the work of the <a href="/article/Intergovernmental_Panel_on_Climate_Change_%28IPCC%29">IPCC</a>’s <em>Climate Change 2007</em> authors, who examined thousands of data records from all over the globe from a much larger time frame. </p><p>The resulting short paper (only 4 pages!) by Michael Mann and Philip Jones is titled “Global surface temperatures over the past two millennia” and opens with this paragraph:</p><blockquote><p><em>We present reconstructions of Northern and Southern Hemisphere mean surface temperature over the past two millennia based on high-resolution &quot;proxy&quot; temperature data which retain millennial-scale variability. These reconstructions indicate that late 20th century warmth is unprecedented for at least roughly the past two millennia for the Northern Hemisphere. Conclusions for the Southern Hemisphere and global mean temperature are limited by the sparseness of available proxy data in the Southern Hemisphere at present.* [8] </em></p></blockquote><p>The first key phrase is “mean surface temperature,” which, in the precise language of science, translates into the average temperature at the Earth’s surface. </p><p>Next, “high-resolution ‘proxy’ <a href="/article/Temperature">temperature</a> data” is a fancy way of saying that where direct written temperature records do not exist, Mann and Jones used stand-ins that could capture small changes in surface temperature. Two millennia ago, Roman and Chinese bureaucrats did record weather and temperature, especially as it assisted in planning <a href="/article/Agriculture">agriculture</a>, maritime navigation, or even military campaigns. But even if those human written records had survived to this day, the standards of measurement and instruments varied widely, even within the same empire. We’d have a hard time calibrating them to the modern thermometer scale devised by Mr. Anders Celsius. However, mollusk shells in the Chesapeake Bay record the accurate temperature of the water around them before they lock that reading in when they fossilize. This shell record is read by analyzing the exact chemical makeup of the shells, for example, how much calcium and magnesium they contain, and is available going all the way back to 200 BC. The rings of ancient fossil trees in Mongolia depict annual temperatures accurately back to AD 264. Ice cores, lake sediment, and tree rings in eastern Asia are available back to AD 1. Ultra-long-lived trees of western North America yield ring temperature data back to AD 200. And so on. </p><p>The next phrase, “retain millennial-scale variability,” is important as well. It means that these records have the capacity to stay accurate over a long time, 1,000 years at minimum in this case. </p> <p>By comparing these multiple sources, researchers can painstakingly reconstruct the likely average annual temperatures for large areas of the globe. In this case, there are enough parallel and overlapping records from sites in the northern hemisphere to determine that “late 20th century warmth is unprecedented for at least roughly the past two millennia for the Northern Hemisphere.” The same survey for natural records in the southern hemisphere turns up fewer indicators. The southern hemisphere contains far less land surface area on which trees can accumulate rings, bays their shell beds, or lakes their sediment. The existing natural records in the southern hemisphere point in the same temperature direction as those in the northern hemisphere but are simply fewer in number. </p><p>This 2003 study by Mann and Jones is based on assimilating the studies of many other individual climate records as verified by a committee of the US National Academy of Sciences. These studies, in turn, are based on just as rigorous a set of hurdles for the quality and reliability of the data that are included in the research. In fact, Mann and Jones rejected one study they felt was flawed and did not meet their more rigorous standards for reliability. They concluded that their reconstructions support previous conclusions “with regard to the anomalous nature of the late 20th century <a href="/article/Temperature">temperature</a>.” We can detect a prior era of moderately warmer conditions between about AD 800 and 1400 in Figure 2.1. But Mann and Jones write, “Any [northern] hemispheric warmth during that interval is dwarfed by the magnitude of the 20th century warmth.” [8] </p> <p>Is the science objective? Yes, science is a continually self-correcting process. Mann and Jones performed separate analyses of eight regional temperature records for the northern hemisphere and five for the southern hemisphere. There were fewer reliable temperature records for the southern hemisphere. Some of the southern hemisphere measures showed a lower correlation with verification measures that were entirely independent of the northern hemisphere. Therefore, being cautious as good scientists, Mann and Jones concluded that their study supports the previous conclusions about the rise in late 20th century temperatures in the northern hemisphere but that the “sparseness of available proxy data in the Southern Hemisphere lead to less definitive conclusions for [it] or global mean temperature at present.” They included the available, accurate southern hemisphere proxy data trends because they wanted to include both hemispheres to compile a picture of global surface temperatures, even though “previous work has emphasized the Northern Hemisphere and the past 1000 years for which adequate proxy data have been available.” Should more temperature indicators be uncovered for the southern hemisphere, the study can be done over again to incorporate this fuller set of data. This openness to replication is why we say science is a self-correcting process.</p> <p>Coda: Five years after the study we examined above, Professor Mann went back to this question, how to reconstruct proxy-based <a href="/article/Temperature">temperature</a> variations over the past two millennia. In a six-page paper published in 2008, Mann and his collaborators reported their results after examining 1,209 sets of proxies for temperature. In other words, in just the intervening years since 2003, researchers had discovered hundreds of new proxy indicators or built reliable models for analyzing these additional natural record keepers. At least 25 of the proxies showed temperature records all the way back to 1 BC—a full 2,000 years ago. What did having 50 times more data show Mann and his colleagues? </p><blockquote><p><em>We find that the hemispheric-scale warmth of the past decade for the [Northern Hemisphere] is likely anomalous in the context of not just the past 1,000 years, as suggested in previous work, but longer…. Conclusions are less definitive for the [Southern Hemisphere (SH)] and globe, which we attribute to larger uncertainties arising from the sparser available proxy data in the SH. Given the uncertainties, the SH and global reconstructions are compatible with the possibility of warmth similar to the most recent decade during brief intervals of the past 1,500 years. [9]</em></p></blockquote><p>This is research talk for “all the data show that the <a href="/article/Global_warming">warming</a> of the northern hemisphere during the past 1,000 years is real and unusual” and “we have much less data for the southern hemisphere, but it points in this same warming direction as we are experiencing now.” </p><p>*Mann ME, Jones PD (2003) Global surface temperatures over the past two millennia. Geophysical Research Letters 30(15): 1820, doi:10.1029/2003GL017814. </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_2'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_2 Tue, 27 Oct 2009 22:45:23 GMT http://www.eoearth.org/article/Climate_Solutions~_Chapter_1 <a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_1'><img border='0' src='/upload/thumb/2/2e/F01.01a_SchneiderPPTslide11-onscreenedits.jpg/280px-F01.01a_SchneiderPPTslide11-onscreenedits.jpg' width='100'/></a> <p><strong>Summary of the IPCC Assessment Reports</strong>*</p><blockquote><p><em>The Kyoto treaty would have wrecked our economy, if I can be blunt.</em><br />—George W. Bush, President, United States, 2005</p><p><em>While the Kyoto Protocol is a crucial step forward, that step is far too small. And as we consider how to go further still, there remains a frightening lack of leadership.</em><br />—Kofi Annan, Secretary-General, United Nations, 2006</p><p><em>Global warming has felt like breaking news a few times in recent years. But the first big pulse of coverage and public attention came in 1988, when the Amazon rain forest and Yellowstone were ablaze, a searing drought had farmers kicking dusty fields in frustration, and global temperatures had seen enough of a rise that a NASA climate expert, James Hansen, asserted before a Senate panel that statistics showed “the greenhouse effect has been detected and is changing our climate now.” ^[7]</em><br />—Andrew Revkin, 2008  </p></blockquote><p>*This content is adapted from summaries in the <a href="http://www.ipcc.ch/pdf/10th-anniversary/anniversary-brochure.pdf" class='external text' title="http://www.ipcc.ch/pdf/10th-anniversary/anniversary-brochure.pdf">UNFCCC 10th Anniversary Brochure</a>, and the <a href="http://www.ipcc.ch/" class='external text' title="http://www.ipcc.ch/">IPCC Web site</a>. </p><p>The World Meteorological Organization held the first ever World Climate Conference in 1979 to address concerns that human activities were interfering with regional and global climate patterns. In 1985, WMO, <a href="/contributor/UNEP">UNEP</a>, and the International Council for Science (ICSU) held a joint conference on the Assessment of the Role of Carbon Dioxide and of Other Greenhouse Gases in Climate Variations and Associated Impacts and established the Advisory Group on Greenhouse Gases (AGGG) as follow-up. Two years later at the 10th Congress of the WMO came the call for an “objective, balanced and internationally coordinated scientific assessment of the understanding on the effects of increasing concentrations of <a href="/article/Greenhouse_gas">greenhouse gases</a> on the earth’s climate and on ways in which these changes may impact socio-economic patterns.” The WMO Executive Council asked the secretary-general of the WMO, in coordination with the executive director of UNEP, to create an “ad-hoc international mechanism” to do this. In November 1988, the WMO and UNEP collaborated to form a new panel with a long name and charged it to report back within 2 years. They called it the <a href="/article/Intergovernmental_Panel_on_Climate_Change_%28IPCC%29">Intergovernmental Panel on Climate Change (IPCC)</a>. </p><p>The Panel’s First Assessment Report in 1990 was a landmark synthesis of global climate information. Working Group I experts concluded they were “certain that emissions from human activities are substantially increasing the <a href="/article/Atmospheric_composition">atmospheric</a> concentrations of <a href="/article/Greenhouse_gas">greenhouse gases</a> and that this will enhance the <a href="/article/Greenhouse_effect">greenhouse effect</a> and result in an additional <a href="/article/Global_warming">warming</a> of the Earth’s surface.” [4] Working Group II “highlighted important uncertainties with regard to timing, magnitude and regional patterns of climate change, but noted that impacts will be felt most severely in regions already under stress, mainly in developing countries.” [4] Working Group III “presented a flexible and progressive approach comprising shorter-term mitigation and adaptation measures and proposals for more intensive action over the longer-term. The group developed also possible elements for inclusion in a framework convention on climate change.” [4] It was this last piece from Working Group III that contained the ideas around which UN diplomats formulated the <a href="/article/United_Nations_Framework_Convention_on_Climate_Change_%28full_text%29">UN Framework Convention of Climate Change</a> that became law in 1994.</p><p>The Second Assessment Report, completed in late 1995, included a new area, namely the socioeconomic aspects of climate change, and the scope of the reporting from working groups adjusted to meet this new requirement. The membership of the Panel expanded to include all the member nations of the WMO and UNEP. The 1995 Working Group I concluded that the basic science showed the following:</p><ul><li><a href="/article/Greenhouse_gas">Greenhouse gas</a> concentrations had continued to increase.</li><li>Anthropogenic <a href="/article/Aerosols">aerosols</a> tended to produce negative radiative forcing.</li><li>Climate had changed over the past century.</li><li>The balance of evidence suggested a discernible human influence on global climate.</li><li>Climate was expected to continue to change in the future; and there remained still many uncertainties.</li></ul><p>The 1995 Working Group II concluded, in parallel findings: </p><ul><li>Human-induced climate change added an important new stress.</li><li>Most systems were sensitive to climate change.</li><li>Impacts were difficult to quantify, and existing studies were limited in scope.</li><li>Successful adaptation depended upon technological advances, institutional arrangements, availability of financing, and information exchange.</li><li>Vulnerability increased as adaptive capacity decreased.</li><li>Detection would be difficult, and unexpected changes could not be ruled out; further research and monitoring were essential.</li></ul><p>The 1995 Working Group III highlighted a number of insights for policymakers, such as the following:</p><ul><li>A prudent way to deal with climate change would be through a portfolio of actions aimed at mitigation, adaptation, and improvement of knowledge. </li><li>Earlier mitigation action might increase flexibility in moving toward stabilization of <a href="/article/Atmospheric_composition">atmospheric</a> concentrations of greenhouse gases. </li><li>Significant &quot;no-regrets&quot; opportunities were available in most countries, and the risk of aggregate net damage due to climate change, consideration of risk aversion, and application of the precautionary principle provided rationales for action beyond no regrets. </li></ul><p>The Group also stressed the value of obtaining better information about climate processes, their impacts and responses, and the need for more research and analysis of economic and social issues related to climate change. </p><p>By 2001, the Panel’s Third Assessment Report extended the earlier work and took advantage of increasingly sophisticated observation tools and modeling methods that allowed greater resolution in the findings. The key findings of 2001 Working Group I included these: </p><ul><li>An increasing body of observations gave a collective picture of a warming world and other changes in the climate system. </li><li>Emissions of greenhouse gases and aerosols due to human activities continued to alter the atmosphere in ways that were expected to affect the climate. </li><li>Confidence in the ability of models to project future climate had increased; there was new and stronger evidence that most of the warming over the last 50 years was attributable to human activities.</li><li>Human influences would continue to change atmospheric composition throughout the 21st century.</li><li>Global average <a href="/article/Temperature">temperature</a> and sea level were expected to rise under all IPCC emissons scenarios; atmospheric climate change would persist for many centuries.</li><li>Further action was required to address remaining gaps in information and understanding.</li></ul><p>The 2001 findings of Working Group II included these: </p><ul><li>Recent regional climate changes, particularly temperature increases, had already affected many physical and biological systems. </li><li>There were preliminary indications that some human systems had been affected by recent increases in floods and droughts. </li><li>Natural systems were vulnerable to climate change, and some would be irreversibly damaged. </li><li>Many human systems were sensitive to climate change, and some were vulnerable. </li><li>Projected changes in climate extremes could have major consequences; the potential for large-scale and possibly irreversible impacts posed risks that had yet to be reliably quantified. </li><li>Adaptation was a necessary strategy at all scales to complement climate change mitigation efforts. </li><li>Those with the fewest resources had the least capacity to adapt and were the most vulnerable; and adaptation, sustainable development, and enhancement of equity could be mutually reinforcing. </li></ul><p>The 2001 Working Group III on adaptation and mitigation reported that the desired mix of options to reduce human-induced climate change varied with time and place. Some other key findings included these: </p><ul><li>Near- and long-term implications of stabilizing atmospheric concentrations of greenhouse gases were determined. </li><li>Technologies, policies, and costs of near- and long-term mitigation were identified. </li><li>Alternative development paths could result in very different greenhouse gas emissions. </li></ul><ul><li>Interactions between climate change and other environmental issues and development were xxxxx ,</li><li>Climate change mitigation would both be affected by, and have impacts on, broader socioeconomic policies and trends, such as those relating to development, <a href="/article/Sustainability">sustainability</a>, and equity. </li><li>Significant progress relevant to greenhouse gas emissions reduction had been made since the Second Assessment Report in 1995 and had been faster than anticipated. </li><li><a href="/article/Forest_biome">Forests</a>, <a href="/article/Agriculture">agricultural lands</a>, and other terrestrial <a href="/article/Ecosystem">ecosystems</a> offered significant <a href="/article/Carbon">carbon</a> mitigation potential. </li></ul><ul><li>Although not necessarily permanent, conservation and sequestration of carbon might allow time for other options to be further developed and implemented. </li><li>Most model results indicated that known technological options could achieve a broad range of atmospheric <a href="/article/Carbon_dioxide">CO₂</a> stabilization levels, such as 550 ppmv , 450 ppmv, or below over the next 100 years or more, but implementation would require associated socioeconomic and institutional changes. </li><li>Some sources of greenhouse gas emissions could be limited at no or negative social costs to the extent that policies could exploit no-regrets opportunities. </li><li>Emission constraints in Annex I (industrialized) countries had been well established, though there had been varied “spillover” effects on non–Annex I countries. </li><li>The effectiveness of climate change mitigation could be enhanced when climate policies were integrated with the non-climate objectives of national and sectoral policy development.</li></ul><p>By 2007, the Panel’s Fourth Assessment Report, titled Climate Change 2007, reached stronger consensus on both the rapidity with which climate has been changing and the significance of the human contribution to climate disruption. Dan Perlman and James Morris of Brandeis University sum up the key new findings of the 2007 working groups on the science, adaptation and mitigation options, and policymaking insights in a few sentences, adapted below from their “What the IPCC Said” booklet:</p><ul><li>Warming of the climate system is unequivocal, and it is greater than what was found in the IPCC’s Third Assessment Report in 2001. </li><li>Human activities, in particular the burning of fossil fuels and changes in land use, have resulted in <a href="/article/Global_warming">warming</a> of the planet; other changes in climate; and effects on natural <a href="/article/Ecosystem">ecosystems</a>.</li><li>The climate will continue to change in the 21st century. Specifically, we will see continued increases in <a href="/article/Temperature">temperature</a>, increases in global <a href="/article/Greenhouse_gas">greenhouse gas</a> emissions, and changes in other aspects of climate, such as <a href="/article/Wind">wind</a> patterns and <a href="/article/Precipitation_and_fog">precipitation</a> (Working Group II).</li><li>We can respond to climate change in two ways. Adaptation involves developing ways to protect ourselves from climate impacts, such as building sea walls to protect communities from rising sea levels. Mitigation involves slowing the process of climate change by lowering the concentration of greenhouse gases in the <a href="/article/Atmospheric_composition">atmosphere</a>, for example, by reducing emissions or planting trees. </li><li>While such strategies have begun, more extensive adaptation and mitigation efforts are required to reduce our vulnerability to climate change. In addition, there are barriers, limits, and costs associated with any of these strategies. </li></ul><p>In the long term, there are many reasons to be concerned about climate change, ranging from increased risk of extinctions to rising sea levels. Adaptation (adjusting our environment to avoid climate impacts) and mitigation (such as decreasing our output of greenhouse gases) are both necessary to reduce adverse impacts of climate change. It will probably be possible to stabilize greenhouse gas concentrations in the atmosphere using technologies that are or will soon be available. We need to carefully evaluate both (1) the up-front economic costs of mitigation and (2) the noneconomic and economic costs of the impacts of climate change. </p><p>On the topic of whether and to what extent human activities influence greenhouse gases and climate, the Panel has made the following statements, summarized in Table 1.2, that show a steady march toward near certainty. This rise in certainty is due to both more information from more locations over time and higher-resolution modeling over time based on that information. </p> <p><a href='http://www.eoearth.org/article/Climate_Solutions~_Chapter_1'>Read Full Article...</a></p> http://www.eoearth.org/article/Climate_Solutions~_Chapter_1 Tue, 27 Oct 2009 22:43:40 GMT