evidence: Despite the many climate "skeptics" in key positions of power today, 97 percent of working climate scientists agree that the warming of Earth’s climate over the last 100 years is mainly due to human activity that has increased the amount of greenhouse gases in the atmosphere. Why are they so sure? [...] Moreover, according to the World Radiation Center, the sun’s radiation has not increased since at least 1978 (when satellite monitoring began) though global temperatures over the last 30 years have continued to rise. [...] Evidence from ocean sediments, ice cores, tree rings, sedimentary rocks and coral reefs show that the current warming is occurring 10 times faster than it did in the past when Earth emerged from the ice ages, at a rate unprecedented in the last 1,300 years.