Climate expert visits ICTP

Computer models that perform high-resolution climate simulations will continue to play a key role in addressing causes and mitigation strategies for global warming, according to Warren Washington, a senior scientist at the US National Center for Atmospheric Research and a climate modelling expert.

In a speech delivered at ICTP on 24 September, Dr. Washington, who developed one of the first climate models in the 1960s, described the importance of climate models not only for predicting future changes but also in producing scenarios based on various emission strategies.

"Climate models have evolved over the past 40 years from very simple input models requiring the cooperation of a handful of scientists to ones that today draw input from hundreds of scientists from various disciplines. These models are producing increasingly accurate predictions," said Washington.

These predictions have formed the basis for the Nobel Peace Prize-winning Intergovernmental Panel on Climate Change's (IPCC) assessment reports, which concluded that human activity is changing the Earth's climate through the emission of greenhouse gases and that significant global warming is taking place.

Global warming critics, however, counter that the earth is actually entering a cooling period, or that the warming trend is due to natural variability and not humans. "The cooling trends proposed by sceptics are a misinterpretation of variability and statistical trends," said Washington, adding, "The trend clearly shows a warming pattern. Natural variations do not explain observed long term climate change; the models clearly show that anthropogenic forcings are causing global warming."

Crucial for the future development of climate models are better satellites, according to Washington.  "With improved satellites, modellers can validate their data, and parties to emissions protocols can monitor global greenhouse gases to enforce limits," he said, adding that global climate models also need more details on the regional aspects of climate change, such as those that can be supplied by ICTP's regional climate model RegCM.