Global warming is real article
Global warming is "unequivocal." Sea levels are creeping up at the fastest rate in 2, 000 years. Concentrations of CO2 in the atmosphere have reached "levels unprecedented in at least the last 800, 000 years" (or before modern humans evolved). Most importantly "human influence on the climate system is clear" and "continued emissions of greenhouse gases will cause further warming." Those are some of the key messages in the "Summary for Policymakers" of the physical science of global warming from the Intergovernmental Panel on Climate Change released on September 27.
"The planet is red" in a global map of the change in average surface temperatures, noted Swiss climate scientist Thomas Stocker, co-chair of IPCC Working Group I responsible for this summary at a press conference. "The world is warming."
In the time since the 2007 version of this report, the human effect on the climate has grown more than 40 percent stronger, thanks to continued emissions of greenhouse gases and more precision in measurements, with carbon dioxide leading the charge. That molecule—released by the gigaton from human activities like fossil fuel burning and clearing forests—causes the bulk of global warming. The good news is that extreme global warming by century's end, anything above 3 degrees C or more, seems "extremely unlikely, " in the words of the IPCC.
That's a fact likely to be seized on by those who wish to deny climate change. But, in some sense, this summary is aimed directly at countering some of the misinformation and misinterpretation around climate change. So the report notes that the current "pause" in new global average temperature records since 1998—a year that saw the second strongest El Nino on record and shattered warming records—does not reflect the long-term trend and may be explained by the oceans absorbing the majority of the extra heat trapped by greenhouse gases as well as the cooling contributions of volcanic eruptions. The Medieval Warm Period was only a regional anomaly, not the kind of global warming seen now. After all, 1983-2012 appears to have been the warmest period in at least the last 1400 years and the last decade alone is the warmest on record.