The Arctic Monitoring and Assessment Programme (AMAP) says unless action is taken to reduce greenhouse gas emissions, ocean levels will increase by between 0.9 and 1.6 metres in this century.
That’s two to three times greater than the range predicted in the last Intergovernmental Panel on Climate Change report, which did not include the impact of Arctic ice melting.
The Snow, Water, Ice and Permaforst in the Arctic report is based on the latest scientific research into the state of the cryosphere, the part of the Earth’s surface that is seasonally or perennially frozen. Its Key Findings include:
- The past six years (2005–2010 have been the warmest period ever recorded in the Arctic Higher surface air temperature are driving changes in the cryosphere.
- There is evidence that two components of the Arctic cryosphere – snow and sea ice are interacting with the climate system to accelerate warming.
- The extent and duration of snow cover and sea ice have decreased across the Arctic. Temperatures in the permafrost have risen by up to 2 °C. The southern limit of permafrost has moved northward in Russia and Canada.
- The largest and most permanent bodies of ice in the Arctic – multiyear sea ice, mountain glaciers, ice caps and the Greenland Ice Sheet – have all been declining faster since 2000 than they did in the previous decade.
- Model projections reported by the Intergovernmental Panel on Climate Change (IPCC) in 2007 underestimated the rates of change now observed in sea ice.
- Maximum snow depth is expected to increase over many areas by 2050, with greatest increases over Siberia. Despite this, average snow cover duration is projected to decline by up to 20% by 2050.
- The Arctic Ocean is projected to become nearly ice-free in summer within this century, likely within the next thirty to forty years.
- Changes in the cryosphere cause fundamental changes to the characteristics of Arctic ecosystems and in some cases loss of entire habitats. This has consequences for people who receive benefits from Arctic ecosystems.
- The observed and expected future changes to the Arctic cryosphere impact Arctic society on many levels. There are challenges, particularly for local communities and traditional ways of life. There are also new opportunities.
- Transport options and access to resources are radically changed by differences in the distribution and seasonal occurrence of snow, water, ice and permafrost in the Arctic. This affects both daily living and commercial activities.
- Arctic infrastructure faces increased risks of damage due to changes in the cryosphere, particularly the loss of permafrost and land-fast sea ice.
- Loss of ice and snow in the Arctic enhances climate warming by increasing absorption of the sun’s energy at the surface of the planet. It could also dramatically increase emissions of carbon dioxide and methane and change large-scale ocean currents. The combined outcome of these effects is not yet known.
- Arctic glaciers, ice caps and the Greenland Ice Sheet contributed over 40% of the global sea level rise of around 3 mm per year observed between 2003 and 2008. In the future, global sea level is projected to rise by 0.9–1.6 m by 2100 and Arctic ice loss will make a substantial contribution to this.
- Everyone who lives, works or does business in the Arctic will need to adapt to changes in the cryosphere. Adaptation also requires leadership from governments and international bodies, and increased investment in infrastructure.
- There remains a great deal of uncertainty about how fast the Arctic cryosphere will change in the future and what the ultimate impacts of the changes will be. Interactions (‘feedbacks’) between elements of the cryosphere and climate system are particularly uncertain. Concerted monitoring and research is needed to reduce this uncertainty.
Joe Romm writes in Climate Progress that this report’s predictions are conservative, because they do not include feedback effects that are likely to release methane from the Arctic permafrost when temperatures rise.