Global Climate Change: Seeking a Global Consensus : Hearing Before the Committee on Commerce, Science, and Transportation, United States Senate, One Hundred First Congress, Second Session ... June 14, 1990U.S. Government Printing Office, 1990 - 56 pages |
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action agriculture Alan Hecht areas Assessment of Climate assessment report atmospheric concentrations BERNTHAL Bolin carbon cycle carbon dioxide CFCs Chairman chlorofluorocarbons climate change response climate models coastal concentrations at today's concentrations of greenhouse consensus considered decade developing countries draft ecosystems emission scenarios energy environmental executive summary final future climate Geneva global change global climate change global mean temperature global warming greenhouse effect greenhouse gas emissions greenhouse gases hearing human activities improve our predictive increase Intergovernmental Panel IPCC Working Groups issue Lead Authors long-lived gases magnitude meeting methane National negotiation nitrous oxide oceans Panel on Climate patterns of climate permafrost policy options policymakers summary potential problem recognized response strategies RSWG Saudi Arabia Scientific Assessment scientists sea level rise Senator GORE significant statement Strategies Working Group Subgroup task three working groups tions today's levels uncertainties understand United Kingdom USSR Watson week WG-I WG-II World Meteorological Organization
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Page 12 - There are many uncertainties in our predictions particularly with regard to the timing, magnitude and regional patterns of climate change, due to our incomplete understanding of: • sources and sinks of greenhouse gases, which affecl predictions of future concentrations.
Page 12 - ... sources and sinks of greenhouse gases, which affect predictions of future concentrations clouds, which strongly influence the magnitude of climate change • oceans, which influence the timing and patterns of climate change...
Page 11 - ... atmospheric concentrations of the long-lived gases (carbon dioxide, nitrous oxide and the CFCs) adjust only slowly to changes in emissions. Continued emissions of these gases at present rates would commit us to increased concentrations for centuries ahead. The longer emissions continue to increase at present day rates, the greater reductions would have to be for concentrations to stabilise at a given level. the long-lived gases would require immediate reductions in emissions from human activities...
Page 11 - Earth warmer than it would otherwise be. • emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases: carbon dioxide, methane, the chlorofluorocarbons and nitrous oxide. These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth's surface.
Page 23 - Relatively small climate changes can cause large water resource problems in many areas, especially arid and semi-arid regions and those humid areas where demand or pollution has led to water scarcity. Little is known about regional details of greenhouse-gas-induced hydro-meteorological change.
Page 13 - The size of this warming is broadly consistent with predictions of climate models, but it is also of the same magnitude as natural climate variability. Thus, the observed temperature increase could be largely due to natural variability; alternatively, this variability and other human factors could have offset a still larger human-induced greenhouse warming.
Page 12 - A) emissions of greenhouse gases, a rate of increase of global mean temperature during the next century of about 0.3°C per decade (with an uncertainty range of 0.2°C to 0.5°C per decade); this is greater than that seen over the past 10,000 years. This will result in a likely increase in global mean temperature of about 1°C above the present value by 2025 and 3°C before the end of the next century.
Page 7 - IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). The role of the IPCC is to assess the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.
Page 13 - Rapid changes in climate will change the composition of ecosystems; some systems will benefit, while others will be unable to migrate or adapt fast enough and may become extinct Enhanced levels of carbon dioxide may increase productivity and efficiency of water use of vegetation. The effect of warming on biological processes, although poorly understood, may increase the atmospheric concentrations of natural greenhouse gases.
Page 11 - There is a natural greenhouse effect which already keeps the Earth warmer than it would otherwise be. Emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases, carbon dioxide, methane, chlorofluorocarbons (CFCs) and nitrous oxide. These increases will enhance the greenhouse effect, resulting on average in an additional warming of the Earth's surface. The main greenhouse gas, water vapour, will increase in response to global warming...