May 6, 2014
New Evidence That Human Activities Are To Blame For Global Warming
Brett Smith for redOrbit.com - Your Universe Online
“Multiple lines of independent evidence confirm that human activities are the primary cause of the global warming of the past 50 years,” the report said. “The burning of coal, oil, and gas, and clearing of forests have increased the concentration of carbon dioxide in the atmosphere by more than 40 percent since the Industrial Revolution, and it has been known for almost two centuries that this carbon dioxide traps heat.”
The National Climate Assessment report, which is scheduled to be updated and released every four years, emphasized that average temperatures across the US are rising, mostly in the northern states. Alaska, in particular, has seen some of the greatest temperature increases in the last four decades, the report said.
The report also said Americans are seeing heavier rains during storm events. One chart included in the report showed the northeastern US, including New England, has seen a 71 percent increase in the amount of precipitation that fell during major storms from 1958 to 2012. The report author noted that the increase in precipitation has “frequently led to runoff that exceeded the capacity of storm drains and levees, and caused flooding events and accelerated erosion.”
The report also discussed sea level rise – which has the potential to impact those who make a living in America’s coastal regions. The report said satellite measurements have provided significant data showing the rate of global sea level since 1992 has been double that seen over the entire last century.
“Coastal infrastructure, including roads, rail lines, energy infrastructure, airports, port facilities, and military bases, are increasingly at risk from sea level rise and damaging storm surges,” the report said.
The report, prepared by 300 experts guided by a 60-member Federal Advisory Committee, agreed that a recent report by the United Nations Intergovernmental Panel on Climate Change (IPCC) also found human activity is driving rising temperatures.
John P. Holdren, President Obama's science adviser, told a press conference in Washington on Tuesday that the new comprehensive report is “the loudest and clearest alarm bell to date” for steps toward reducing greenhouse gas emissions.
“These emissions come mainly from burning coal, oil, and gas, with additional contributions from forest clearing and some agricultural practices,” the report said.
Authors of the report made a point to mention the societal impact that global warming is having right now.
"Climate change is here and now, and not in some distant time or place," said report author Katharine Hayhoe, a Texas Tech University climate scientist, told USA Today. "The choices we're making today will have a significant impact on our future.”
"If people took the time to read the report, they would see that it is not necessarily about polar bears, whales or butterflies," he said. "I care about all of those, but the NCA is about our kids, dinner table issues, and our well being."