US unveils climate report in runup to Senate bill

The report, a draft of the Fifth U.S. Climate Action Report that will be sent to the United Nations, says bluntly: “Global warming is unequivocal and primarily human-induced ... Global temperature has increased over the past 50 years. This observed increase is due primarily to human-induced emissions of heat-trapping gases.”

Without action to stop them, climate-warming greenhouse gas emissions will rise over 8,000 megatonnes by mid-century, the draft said. By adopting measures detailed in a bill passed last year by the U.S. House of Representatives, these emissions will drop beneath 2,000 megatonnes. They’re now about 6,500 megatonnes. The United Nations measures greenhouse gas emissions in megatonnes, or million metric tons.

The effects of climate change are already evident, the draft said: warming air and oceans, vanishing mountain glaciers, thawing permafrost, signs of instability in the ice sheets of Greenland and Antarctica and rising sea levels.

The State Department draft, now open for public comment, precedes the expected April 26 unveiling of Senate legislation by Democrat John Kerry, Republican Lindsey Graham and Independent Joe Lieberman.

Supporters of the bill hope this will pave the way for the full Senate to debate and pass a measure in June or July.

The State Department report will ultimately go to the United Nations Framework Convention on Climate Change; previous U.S. reports to this body were in 1994, 1997, 2002 and 2007.