This is Section 1.6 of the Arctic Climate Impact Assessment
Authors: Henry Huntington, Gunter Weller. Contributing Authors: Elizabeth Bush,Terry V. Callaghan,Vladimir M. Kattsov, Mark Nuttall

This assessment contains eighteen chapters. The seventeen chapters that follow this introduction are organized into four sections: climate change and UV radiation change in the Arctic, impacts on the physical and biological systems of the Arctic, impacts on humans in the Arctic, and future steps and a synthesis of the ACIA.

Climate change and UV radiation change in the Arctic (1.6.1)

The arctic climate is an integral part of the global climate, and cannot be understood in isolation. Chapter 2 describes the arctic climate system, its history, and its connections to the global system.This description lays the foundation for the rest of the treatment of climate in this assessment. Chapter 3 lays another essential foundation for the assessment by describing how climate change appears from the perspective of arctic indigenous peoples, a topic also included in other chapters. Chapter 4 describes future climate projections, developed through use of emissions scenarios of greenhouse gases, and climate modeling. Several modeling simulations of future climates were developed specifically for this assessment, and these are described in detail. Chapter 5 provides the counterpart to Chapters 2 and 4 on observations and future projections of UV radiation and ozone, and their effects.The causes and characteristics of ozone depletion are discussed, together with models for the further depletion and eventual recovery of the ozone layer following international action.

Impacts on the physical and biological systems of the Arctic (1.6.2)

The primary impacts of climate change and increased UV radiation in the Arctic will be to its physical and biological systems. Chapter 6 describes the changes that have already been observed, and the impacts that are expected to occur in the frozen regions of the Arctic, including sea ice, permafrost, glaciers, and snow cover. River discharge and river and lake ice break-up and freeze-up are also discussed. Chapter 7 discusses impacts on the terrestrial ecosystems of the Arctic, drawing on extensive research, experimental data, observations, and indigenous knowledge. Biodiversity, risks to species, including displacements due to climate change, UV radiation effects, and feedback processes as the vegetation and the hydrological regime change are discussed. Chapter 8 examines freshwater ecosystems in a similar fashion, including a discussion of freshwater fisheries in the Arctic. Chapter 9 covers the marine systems of the Arctic, and includes topics from the physical ocean regime, including the thermohaline circulation, to sea ice, coastal issues, fisheries, and ecosystem changes.

Impacts on humans in the Arctic (1.6.3)

The implications of climate change and changes in UV radiation for humans are many and complex, both direct and indirect. Chapter 10 addresses the challenges to biodiversity conservation posed by climate change, especially given the relative paucity of data and the lack of circumpolar monitoring at present. Chapter 11 outlines the implications of climate change for wildlife conservation and management, a major concern in light of the substantial changes that are expected to impact upon ecosystems. Chapter 12 looks at traditional practices of hunting, herding, fishing, and gathering, which are also likely to be affected by ecosystem changes, as well as by changes in policies and society. Chapter 13 describes the commercial fisheries of the arctic seas, including seals and whales, with reference to climate as well as to fishing regulations and the socio-economic impacts of current harvests of fish stocks. Chapter 14 extends the geographic scope of the assessment to the northern boreal forest, examining both that ecosystem and the implications of climate change for agriculture and forestry. Chapter 15 discusses the implications of climate and UV radiation on human health, both for individuals and for communities in terms of public health and cultural vitality. Chapter 16 explores the ways in which climate may affect man-made infrastructure in the Arctic, both in terms of threats to existing facilities such as houses, roads, pipelines, and other industrial facilities, and of future needs resulting from a changing climate.

Future steps and a synthesis of the ACIA (1.6.4)

Chapter 17 presents an innovative way of examining societal vulnerability to climate change. It gives some initial results from current research but primarily illustrates prospects for applying this approach more broadly in the future. Chapter 18 contains a synthesis and summary of the main results of the ACIA, including implications for each of the four ACIA regions and directions for future research.

Chapter 1: Introduction to the ACIA

1.1  An Introduction to the Arctic Climate Impact Assessment
1.2. Why assess the impacts of changes in climate and UV radiation in the Arctic?
1.3. The Arctic Climate Impact Assessment
1.4. The assessment process
1.5. The Arctic: geography, climate, ecology, and people
1.6. Outline of the ACIA assessment|An outline of the assessment