The solid scientific consensus on climate change (1) - Record-Searchlight (blog)

The Intergovernmental Panel on Climate Change in 2007 said:

"Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level."

Also:

"Global GHG (greenhouse gas) emissions due to human activities have grown since pre-industrial times, with an increase of 70% between 1970 and 2004. Global atmospheric concentrations of CO2 (carbon dioxide), CH4 (methane) and N2O (nitrous oxide) have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years."

And:

"The atmospheric concentrations of CO2 and CH4 in 2005 exceed by far the natural range over the last 650,000 years. Global increases in CO2 concentrations are due primarily to fossil fuel use."

While some argue that there is still a debate among the world's major climate scientists regarding the cause of global warming, the IPCC states this:

• There is very high confidence that the global average net effect of human activities since 1750 has been one of warming.
• Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.
• It is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent (except Antarctica).
• Discernible human influences extend beyond average temperature to other aspects of climate, including temperature extremes and wind patterns.

In 2007, the IPCC also reported, "Anthropogenic warming over the last three decades has likely had a discernible influence at the global scale on observed changes in many physical and biological systems."

The IPCC is a "scientific intergovernmental body" established by all the Earth's governments including the United States when Ronald Reagan was our president. "Its mission is to provide comprehensive scientific assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its potential environmental and socio-economic consequences, and possible options for adapting to these consequences or mitigating the effects."

Thousands of independent climate scientists from all across our planet have been meeting on an annual basis for nearly 25 years and have produced the most comprehensive, conservative and collaborative reports on any scientific topic in the history of science. These top scientists from the world's most prestigious universities and governmental agencies review all the current studies regarding our climate and produce summary reports that this body of scientists review, discuss, dissect, edit and ultimately agree to support.

These reports are then turned over to representatives from every government on Earth, including the United States. These political officials then review, discuss, dissect, edit and ultimately agree to support these comprehensive scientific documents.

There have been four reports published. The first was in 1990 when George H.W. Bush was president, the second in 1995 during the Clinton administration and the third and fourth reports were released in 2001 and 2007 when George W. Bush was president.

Thousands of the world's top climate scientists and representatives from every government on Earth, including the United States under Republican and Democratic administrations have repeatedly accepted the scientific consensus that humans are responsible for global warming and related changes to our climate. This is not disputed within the scientific community although it remains a hotly debated political topic.

The scientific opinion on climate change is that the Earth's climate system is unequivocally warming, and it is more than 90% certain that humans are causing it through activities that increase concentrations of greenhouse gases in the atmosphere, such as deforestation and burning fossil fuels. This scientific consensus is expressed in synthesis reports, scientific bodies of national or international standing, and surveys of opinion among climate scientists. Individual scientists, universities, and laboratories contribute to the overall scientific opinion via their peer-reviewed publications, and the areas of collective agreement and relative certainty are summarised in these high level reports and surveys."