Tag Archives: climate change

Average temperature to rise by 4 degree Celsius

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The world is heading for an average temperature rise of nearly 4 degree Celsius, according to analysis of national pledges from around the globe. Such a rise would bring a high risk of major extinctions, threats to food supplies and the near total collapse of the huge Greenland ice sheet. More than 100 heads of state agreed in Copenhagen last December to limit the rise in global temperature to 1.5 – 2 degree Celsius above the long term average before the industrial revolution, which kick started a massive global increase in the greenhouse gases blamed for warming the planet and triggering climate change.            global warming

But six months on, a major international effort to monitor the emissions reductions targets of more than 60 countries, including all the major economies, the Climate Interactive Scoreboard, calculates that the world is on course for a rise of nearly double the stated goal by 2100. Another study by Climate Analysts at the Potsdam Institute in Germany suggests there is “virtually no change” world governments will keep the temperature rise below 2 degree Celsius. In the last assessment of the problem in 2007, the Intergovernmental Panel on climate change (IPCC) forecasts that a rise of more than 2 degree Celsius would lead to potential increase in food production, but an increasingly high risk of extinction for 20-30 percent species, severe droughts, floods and a unstoppable “widespread to near total” loss of Greenland ice sheet over very long time periods.

however at 4 degree Celsius it predicted global food production was “very likely” to decrease, “major extinctions around the globe”, and near total loss of Greenland’s ice, precipitating 2-7 meters of sea level rise in the long term. The climate interactive Scoreboard, for which researchers check daily for updates in emissions or other targets which would reduce pollution such as reductions in energy intensity or increase in renewable energy, make a medium-range prediction of a 3.9 degree Celsius increase in temperatures, with a range of 2.3-6.2 degree Celsius, based on committed targets and a more encouraging 2.9 degree Celsius average, with a range of 1.7-4.6 degree Celsius based on “potential” commitments suggested but not enacted by many nations.

Climate Analytics and Ecofys, under the banner of Climate Action Tracker, estimate a range of 2.8-4.3 degree Celsius.

Stopping CO2 emissions cannot avert climate change

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With carbon dioxide (CO2) in the air approaching alarming levels, even halting emissions altogether may not be enough to avert catastrophic climate change. A new study by Carnegie institution scientists suggests that while removing excess CO2 would cool the planet, carbon cycle complexities would limit the effectiveness of a one time effort. To keep CO2 at low levels would require a long term commitment spanning decades or even centuries. Previous studies have shown that reducing CO2 emissions to zero would not lead to appreciable cooling because CO2 already within the atmosphere would continue to trap heat.                       emission

For cooling greenhouse gas concentrations need to be reduced. “We want to see what the response will be if carbon dioxide were actively removed from the atmosphere,” says study co-author Ken Caldeira of Carnegie’s Department of Global Ecology. Caldeira and study co-author Long Cao did not focus on any specific method of capturing and storing CO2 from the air. The posibilities include approaches as diverse as industrial scale chemical technologies and changing land use so more CO2 is naturally absorbed by vegetation.

According to the simulations conducted by the researchers, for every 100 billion tonnes of carbon removed from the atmosphere, average global temperature would drop 0.16 degree Celcius, said a Carnegie institution release. Further simulations showed that in order to keep CO2 at low levels, the process of CO2 extraction from the air would have to continue for many decades, and perhaps centuries, after emissions were halted.