AGU calls for action on climate change

The position statement warns that “the present level of scientific uncertainty does not justify inaction in the mitigation of human-induced climate change and/or the adaptation to it,” and recommends the development of strategies such as “emissions reduction, carbon sequestration, and adaptive measures to limit the impacts of climate change.”

The position statement calls for more international research into man’s effect on climate. “The world may already be committed to some degree of human-caused climate change, and further build-up of greenhouse gas concentrations may be expected to cause further change. Some of these changes may be beneficial and others damaging for different parts of the world. However, the rapidity and uneven geographic distribution of these changes could be very disruptive.”

The AGU statement continues: “Present understanding of the Earth climate system provides a compelling basis for legitimate public concern over future global- and regional-scale changes resulting from increased concentrations of greenhouse gases. These changes are predicted to include increases in global mean surface temperatures, increases in global mean rates of precipitation and evaporation, rising sea levels, and changes in the biosphere.”

The statement says that although greenhouse gas concentrations are projected to increase, the climate system’s inherent complexity and variability make it difficult to predict how the climate system will respond.

“Because of these uncertainties, there is much public debate over the extent to which increased concentrations of greenhouse gases have caused or will cause climate change, and over potential actions to limit and/or respond to climate change.”

The statement says that increases in mean surface temperature over the past 150 years appear to be consistent with the radiative properties of carbon dioxide and with the influence of climate on the carbon cycle. “Fossil records suggest that the transfer of carbon from the Earth’s crust to atmospheric carbon dioxide, in quantities comparable to the burning of fossil fuels, tends to produce changes in other parts of the carbon cycle and climate system.

“This close coupling between atmospheric carbon dioxide and climate suggests that a change in one would in all likelihood be accompanied by a change in the other.”