New evidence suggests climate change is human caused and that if the release of greenhouse gases continues unabated, changes to the world’s climate will greatly exceed those that have taken place so far.
The new joint report from the US National Academy of Sciences and the Royal Society, the national science academy of the UK, is called Climate Change: Evidence and Causes. It predicts Earth’s temperature will rise between 5-to-9 degrees Fahrenheit by the end of the century.
“As two of the world’s leading scientific bodies, we feel a responsibility to evaluate and explain what is known about climate change, at least the physical side of it, to concerned citizens, educators, decision makers and leaders, and to advance public dialogue about how to respond to the threats of climate change,” said the USNAS President Ralph Cicerone.
Even if the release of greenhouse gases were stop immediately temperatures would continue to rise, according to the report.
“If greenhouse gas emissions were to suddenly stop, the earth would not cool to preindustrial levels for thousands of years,” said Inez Fung, the U.S. lead author of the report from the University of California, Berkeley. “The actions of today have long-term effects. Stopping emissions now doesn’t mean we can remove the carbon dioxide that is already in the atmosphere. The accumulation of CO2 in the atmosphere causes continued rises in temperatures and sea levels.”
The report is written in easy-to-understand English, addresses 20 important issues in a question-and-answer format, and explains which characteristics of climate change are well established and documented as well as those that aren’t which require further investigation.
“Climate change is a dividing issue of our times,” said Paul Nurse, head of the Royal Society. “Policy decisions are made on the world stage. This is a simple but authoritative account of the major issues of climate change. It’s a reliable guide to the science – a guide that’s necessary for an informed debate.”
According to the report, current atmospheric C02 levels have risen to a level that hasn’t been seen in about 800,000 years. A review of observational data dating back to the mid-19th century has shown a definite long-term warming trend. Researchers have found that, since 1900, Earth’s average surface air temperature has increased by about 1.4 degrees Fahrenheit and that much of that rise took place in the mid-1970s.
Measurements made by the American and British teams that prepared the report show the increase of atmospheric C02 has been mostly caused by combustion of fossil fuels and not due to naturally occurring phenomena such as changes in the sun’s output as some have suggested.
The reduction in Arctic sea ice, a rise in ocean temperatures as well as changes in nature like the movement of temperature-sensitive species of fish, mammals, insects toward the poles, provide irrefutable evidence of planetary-scale warming, said the report authors.
A number of people living along the East Coast have questioned climate change after being hit with extreme weather conditions this winter brought on by polar vortices. Even with spring only a couple of weeks away, the mid-Atlantic region of the US is being hit today by a major winter storm that has brought with it very cold temperatures as well as treacherous accumulations of snow and ice.
But Fung suggests that climate change may be responsible for the harsh winter weather as well as other forms of extreme weather such as record heat, drought or rainfall.
“A warmer atmosphere can hold more moisture so when it rains, there’s more rain,” she said. “Rainfall will be more intense. Heat waves will become more frequent. We expect droughts, when they occur, will be more severe. There will always be cold nights and cold days in this warming trend, but they will be rarer and rarer.”