A new methodology to tease out how much current climate change is linked to human activities has added to the consensus that behind global warming is us. The study, published in Nature Geoscience found that humans have caused at least three-quarters (74 percent) of current warming, while also determining that warming has actually been slowed down by atmospheric aerosols, including some pollutants, which reflect sunlight back into space.
Running thousands of models based on Earth’s total energy budget, the study came up with findings incredibly similar to other methods. The study found that greenhouse gases have increased global temperatures by 0.85 degrees Celsius since the 1950s, however aerosols knocked that down by 0.45 degrees Celsius, leaving a total warming of 0.5 degrees Celsius. In fact, temperatures around the world have risen 0.55 degrees Celsius since the 1950s.
The study also looked at two counter hypothesis put forward by climate change deniers: solar radiation and natural variation. At most solar radiation added 0.07 degrees Celsius to current warming, a pittance compared to greenhouse gases and only around 12 percent of current warming. In addition, the study found that even if the Earth’s climate were three times more variable than believed, it would still not account for current warming.
Global climate change has been linked to melting of the Arctic sea ice, global sea level rise, increased droughts and floods, worsening extreme weather, desertification, melting glaciers, along with other changes. Predicted impacts have included increased global conflict, famine, disease expansion, economic collapse, and mass extinction.
(12/04/2011) Total carbon emissions for the first time hit 10 billion tonnes (36.7 billion tonnes of CO2) in 2010, according to new analysis published by the Global Carbon Project (GCP) in Nature Climate Change. In the past two decades (since the reference year for the Kyoto Protocol: 1990), emissions have risen an astounding 49 percent. Released as officials from 190 countries meet in Durban, South Africa for the 17th UN Summit on Climate Change to discuss the future of international efforts on climate change, the study is just the latest to argue a growing urgency for slashing emissions in the face of rising extreme weather incidents and vanishing polar sea ice, among other impacts.
(12/01/2011) Purchasing a full page ad in the Canadian paper the Globe and Mail, a group of African leaders and NGOs is calling on Canada to return to the fold on climate change. Canada has recently all-but-confirmed that after the ongoing 17th UN Summit on Climate Change in Durban, South Africa, it will withdraw entirely from the Kyoto Treaty. The country has missed its targets by a long-shot, in part due to the exploitation of its tar sands for oil, and is increasingly viewed at climate conferences as intractable and obstructive. In the eyes of those concerned about climate change, Canada has gone from hero to villain. Yet notable African activists, including Archbishop Desmond Tutu, are pushing back.
(11/30/2011) As officials meet at the 17th UN Climate Summit in Durban, South Africa, the world continues to heat up. The UN World Meteorological Organization (WMO) has announced that they expect 2011 to be the warmest La Niña year since record keeping began in 1850. The opposite of El Nino, a La Niña event causes general cooling in global temperatures.