In his March 21 opinion piece, Mr. Albert Lusk of San Isidro, Heredia, maintains “there is no scientific consensus that humans aid [global] warming.” This is unequivocally not true.
In 2007, the Intergovernmental Panel on Climate Change reported there is a greater than 90 percent certainty that humans are causing climate change through activities that increase concentrations of greenhouse gases in the atmosphere. No scientific body of national or international standing maintains a formal opinion contradicting this view. At least 50 national science academies and other scientific organizations have made formal declarations supporting the conclusion of human-induced global warming while calling for the reduction in greenhouse gas emissions. They range from the American Association for the Advancement of Science to the World Health Organization and from the United States National Research Council to the World Meteorological Organization.
Prior to 2007, the American Association of Petroleum Geologists was the only major scientific organization that rejected the finding of significant human influence on recent climate change. However, that year they revealed their official position was not supported by a significant number of their current and prospective members.
According to Wikipedia, “As of 2007, when the American Association of Petroleum Geologists released a revised statement, no scientific body of national or international standing rejected the findings of human-induced effects on climate change.”
In addition, the International Energy Agency has published data for over 140 countries comparing annual carbon dioxide emissions with GDP. The effect of greenhouse gases such as carbon dioxide on global warming is well-documented. GDP is the standard measure of economic activity, clearly a human endeavor. The relationship between the two is highly linear with a correlation coefficient of 0.80 (where perfect correlation affords a coefficient of exactly 1.00). If you limit the data to those countries which account for over 50 percent of world-wide GDP (the European Union countries, the U.S. and Japan) the correlation coefficient rises to 0.86. And although “correlation does not imply causation,” correlation remains a basic component of scientific method. It simply requires a connection between the cause and the effect through an impact mechanism in accordance with known laws of nature. In this case the impact mechanism is the trapping of heat within the atmosphere by increasing concentrations of greenhouse gases produced from enhanced economic activity.
It is true that there are a relatively small number of individual scientists who disagree with some conclusions of the Intergovernmental Panel on Climate Change report, although many agree there is at least some component of human involvement in the ongoing climate change. Some argue the changes are entirely natural. And still others do research funded in part by the fossil fuel industry, suggesting the potential for conflict of interest.
In the end, the overwhelming view of scientists world-wide is that climate change is largely the result of human activity. It is hard to understand Mr. Lusk’s definition of “scientific consensus,” unless it must require the inclusion of FOX News and the Wall Street Journal.
San Antonio de Belén, Heredia