Thursday, September 27, 2012

The CO2 Tipping Point Not Yet Reached- Oceans and Vegetation Absorb More Carbon

The International Energy Agency, IEA, estimates that world CO2 emissions from fossil fuel combustion rose by 1 billion metric tons in 2011, a 3.2 % increase over 2010 to reach 31.6 billion metric tons (34.83 billion tons). In 2011 the top four world generators of CO2 emission from fossil fuels were in descending order China, the United States, the European Union and India who edged out Russia to take the number four slot. China contributed almost three quarters of the global increase, with its emissions rising by 720 million metric tons, or 9.3% to 8.46 billion metric tons of CO2, primarily due to higher coal consumption to produce electricity. Increases in the CO2 emission from fossil fuel combustion in 2012 is likely to be less since electricity use in China is up only 1% this year.

Nonetheless, the world CO2 emissions continue to increase. IEA not only collects data it also makes progress reports, and makes recommendations for implementing carbon dioxide controls worldwide to preventing the world from reaching the “Tipping Point” where global temperatures cannot be held within 2°C above pre-industrial levels. Initially, the climate science establishment thought the Tipping Point would be reached when world CO2 emissions from burning fossil fuel reached 32.6 billion metric tons of CO2 annually and global CO2 concentrations reached 450 parts per million. The “Tipping Point” was the 450 Scenario which limits global warming to 2 degrees by limiting concentration of greenhouse gases in the atmosphere to around 450 parts per million of CO2. We are currently very close to the 32.6 billion metric tons (just 1 billion metric tons above 2011 levels and the amount the world emissions increased last year.) However, though the atmospheric concentrations of CO2 continue to rise, the National Oceanic & Atmospheric Administration, NOAA, reports that CO2 concentrations have risen just 2.33 parts per million to 392.41 parts per million from August 2011 to August 2012.

Despite sharp increases in carbon dioxide emissions from burning fuel the level of carbon dioxide in the atmosphere has not increased as quickly. There appears to be a buffer provided by Earth’s vegetation and oceanswhich continue to soak up about half of the carbon dioxide emissions each year (though of course impact on marine ecology should be of concern) according to arecently published study led by the University of Colorado at Boulder. The study, led by Dr. Ashley Ballantyne, looked at global CO2 emissions reports from the past 50 years and compared them with rising levels of CO2 in Earth’s atmosphere during that time. The results showed that while CO2 emissions had quadrupled, natural carbon “sinks” that sequester the greenhouse gas doubled their uptake of CO2 in the past 50 years, potentially lessening the warming impacts on Earth’s climate.

The study showed global CO2 uptake by Earth’s sinks essentially doubled from 1960 to 2010, although increased variations from year-to-year and decade-to-decade suggests some instability in the global carbon cycle. According to the study, CO2 uptake by Earth’s land and oceans decreased in the 1990s (when most of the climate models were developed), followed by increased CO2 sequestering by the planet from 2000 to 2010. “Seeing such variation from decade to decade tells us that we need to observe Earth’s carbon cycle for significantly longer periods in order to help us understand what is occurring,” said Dr. Ballantyne. Marine Biologists are deeply concerned about the impact of increasing uptake of CO2 by the world’s oceans. Dissolved CO2 in the ocean forms carbonic acid making the oceans more acidic and damaging coral, the fundamental structure of coral reef ecosystems that harbor 25% of the world’s fish species.Take a look at the article in Nature (if you want to spend the money).

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