Showing what one person can do, American climatologist James Hansen testified before a Senate committee in June 1988 warning about global warming and the greenhouse effect, alerting the public to the perils of climate change and was a turning point in the public debate. As Roger Pielke said Hansen’s “call to action.. elevated the subject of global warming and the specter of associated impacts such as more hurricanes, floods, and heat waves, to unprecedented levels of attention from the public, media, and policy makers”.