Monthly Archives: August 2011

A: Yes, it is an unequivocal fact that the Earth’s average temperature continues to rise, despite some natural year-to-year fluctuations. The hottest 10 years on record have all taken place in the past dozen years. Each of the past three … Continue reading

A: Weather and climate are not the same. Weather is individual, day-to-day atmospheric events; climate is the statistical average of those events. Weather is short-term and chaotic and is thus inherently unpredictable beyond a few days. Climate is long-term average … Continue reading

A: Climate changes observed over recent decades are inconsistent with trends caused by natural forces but are totally consistent with the increase in human-induced heat-trapping gases. In fact, without human influences, Earth’s climate actually would have cooled slightly over the … Continue reading

A: Scientists with relevant expertise agree that the world is unequivocally warming. They also agree that human activity is the primary cause of the warming experienced over the past 50 years. This conclusion is based on multiple lines of evidence, … Continue reading

A: Scientists have been measuring the amount of the Sun’s energy reaching the top of Earth’s atmosphere using sensors on satellites since 1978. Since that time, global temperatures have risen sharply, while there has been no trend in the amount … Continue reading

A: No. The urban heat island effect is undoubtedly a real phenomenon that has been recorded in major cities around the world. It results from the large amounts of concrete and asphalt in cities absorbing and holding heat and the … Continue reading

A: We know from ice core records that temperature and carbon dioxide (CO2) levels are closely correlated. In the distant past, warming episodes appear to have been initiated by cyclical changes in Earth’s orbit around the Sun that caused more … Continue reading

A: While some media outlets carried this story back in the 1970s, most climate scientists at the time were not concerned about global cooling. Though climate science was less developed at that time, the vast majority of climate science papers … Continue reading

A: No. The “hockey stick” is a reconstruction of temperatures over the past 1,000 years, using tree-rings, ice cores, corals, and other proxies for temperature before thermometer records began. The principal finding of the original paper, by Michael Mann and … Continue reading

A: No. Early analyses of satellite data by one group in Alabama did suggest that there was little or no warming in the layer of atmosphere just above the surface (the troposphere). It turned out that there were several serious … Continue reading

A: No. Two small errors have been found in one of the IPCC 2007 reports. Neither has anything to do with the basic conclusions that the globe is unequivocally warming and that human activity is the primary cause. These mistakes … Continue reading

A: No. The burning of fossil fuels results in several hundred times as much CO2 release as volcanoes each year. Fossil fuel burning results in the emission of approximately 35 gigatons (billion metric tons) of carbon dioxide into the atmosphere … Continue reading

A: Climate models are mathematical representations of the interactions between the various aspects of the climate system including the atmosphere, oceans, land surface, ice, and the Sun. The complex task of simulating Earth’s climate is carried out by computer programs … Continue reading