Major climate change is inevitable, according to Professor Chris Folland of the UK Hadley Centre for Climate Prediction and Research.
Folland told Laboratory employees at a talk last week that based on his analysis of sea surface, land surface air, and night-time ocean surface air temperatures, the world's climate is warming.
Folland's talk, "The Science of Global Warming and Natural Climate Variability," discussed whether or not climate change is happening, why it is happening, the role of natural variability, and predicting climate change.
He pointed to receding glaciers and sea ice as indicators of a warming climate. He says that there has been global warming of at least .4 to .8 degrees Celsius over the last century and that the last decade was probably the warmest in the last millennium.
There are three suggested causes of this warming: human “forcing” factors, natural internal climate variables, and natural external forcing factors, he said. Natural internal climate variables generally involve the oceans while natural external factors include the sun and volcanoes.
Folland then showed graphs of actual recorded temperatures against a computer model’s predicted temperatures. When actual temperatures were plotted with temperatures predicted by a model that only included natural internal variables and natural external variables, the predicted temperatures varied greatly from the actual temperatures. However, when the model included man-made factors with the natural internal and external variables, the predicted temperatures were nearly identical to actual temperatures. Thus, Folland concludes that natural internal variables and natural external variables cannot explain global warming alone. Man-made factors are an important component of global warming, he said.
He also said that computer models are predicting that the Earth will experience more heat waves on land, fewer cold frost days on land, more intense rainfall, and increased risk of drought in some areas.
Folland concluded that there are many prediction uncertainties, but all models, without exception, predict substantial warming of the Earth.
The talk was hosted by the International, Space and Response Division (ISR) and the Threat Reduction Directorate.
