• We are certain of the following: there is a natural greenhouse effect...; emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases: CO₂, methane, 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 and further enhance it.

• We calculate with confidence that: ...CO₂ has been responsible for over half the enhanced greenhouse effect; long-lived gases would require immediate reductions in emissions from human activities of over 60% to stabilise their concentrations at today's levels...

• Based on current models, we predict: under [BAU] increase of global mean temperature during the [21st] century of about 0.3 ^oC per decade (with an uncertainty range of 0.2 to 0.5 ^oC per decade); this is greater than that seen over the past 10,000 years; under other ... scenarios which assume progressively increasing levels of controls, rates of increase in global mean temperature of about 0.2 ^oC [to] about 0.1 ^oC per decade.

• 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 GHGs; clouds; oceans; polar ice sheets.

• Our judgement is that: global mean surface air temperature has increased by 0.3 to 0.6 ^oC over the last 100 years...; 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 increase could be largely due to this natural variability; alternatively this variability and other human factors could have offset a still larger human-induced greenhouse warming. The unequivocal detection of the enhanced greenhouse effect is not likely for a decade or more.

• under the IPCC business as usual emissions scenario, an average rate of global mean sea level rise of about 6 cm per decade over the next century (with an uncertainty range of 3 – 10 cm per decade), mainly due to thermal expansion of the oceans and the melting of some land ice. The predicted rise is about 20 cm ... by 2030, and 65 cm by the end of the next century.

See also

• Avoiding dangerous climate change
  Avoiding Dangerous Climate Change
  The related terms "avoiding dangerous climate change" and "preventing dangerous anthropogenic interference with the climate system" date to 1995 and earlier, in the Second Assesment Report of the International Panel on Climate Change and previous science it cites.In 2002, the United Nations...
  
  
• Business action on climate change
  Business action on climate change
  Business action on climate change includes a range of activities relating to global warming, and to influencing political decisions on global-warming-related regulation, such as the Kyoto Protocol...
  
  
• Energy conservation
  Energy conservation
  Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption from conventional energy sources...
  
  
• Energy policy
  Energy policy
  Energy policy is the manner in which a given entity has decided to address issues of energy development including energy production, distribution and consumption...
  
  
• Global climate model
  Global climate model
  A General Circulation Model is a mathematical model of the general circulation of a planetary atmosphere or ocean and based on the Navier–Stokes equations on a rotating sphere with thermodynamic terms for various energy sources . These equations are the basis for complex computer programs commonly...
  
  
• Individual and political action on climate change
  Individual and political action on climate change
  Individual and political action on climate change can take many forms, most of which have the ultimate goal of limiting and/or reducing the concentration of greenhouse gases in the atmosphere, toward avoiding dangerous climate change.-Political action:...
  
  
• Precautionary principle
  Precautionary principle
  The precautionary principle or precautionary approach states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those...
  
  
• World energy resources and consumption
  World energy resources and consumption
  ]World energy consumption in 2010: over 5% growthEnergy markets have combined crisis recovery and strong industry dynamism. Energy consumption in the G20 soared by more than 5% in 2010, after the slight decrease of 2009. This strong increase is the result of two converging trends...
  
  

External links

• IPCC 1990 FAR - Working Group I: Scientific Assessment of Climate Change
• IPCC 1990 FAR - Working Group II: Impacts Assessment of Climate Change
• IPCC 1990 FAR - Working Group III: The IPCC Response Strategies