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. Each of the past several decades has been substantially warmer than the decade prior to it. The hottest five years … Continue reading

A: When people wonder about the degree of certainty in global warming predictions versus next week’s weather report, they are confusing climate and weather. Predicting weather and predicting climate are different and pose different challenges. Weather is individual, day-to-day atmospheric events; … 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: More than 97% of climate scientists have concluded that human caused global warming is happening. It is well established that human activity is the dominant cause of the warming experienced over the past 50 years. This conclusion is based … 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: The vast majority of published climate science papers in the 1970s were related to the same concern that prevails today: warming due to the increase in heat-trapping gases. There were a few papers published at that time on the issue … Continue reading

A: Volcanoes can and do influence global climate, exerting a cooling influence for a few years. This cooling influence occurs when large, explosive volcanic eruptions inject sulfate particles into the high reaches of the atmosphere (the stratosphere). For example, the four … 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