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Global Issues
Sea Level rising
The deep ocean seafloor is often a cold, dark place, barren of life. But from time to time a large bounty such as a whale carcass will drift down from the surface. Then sea life explodes: all manner of worms and other invertebrates arrive in larval form to colonize the dead organic matter and population increases dramatically — for a short time. Inevitably the resource dwindles and the population collapses.
In a similar fashion, humans now live upon the resource of dead organic matter. We’ve found our dead whale below ground, in the form of oil, gas and coal — the fossil remains of plants that lived long ago.
Fossil energy has fueled the advent and development of the industrial age and allowed human population to explode. The product of our industrial respiration, carbon dioxide (CO2), has increased in the atmosphere and now threatens to spoil our nest. The atmosphere does more than provide us with oxygen to breathe, it controls the heat balance of the world. The trouble is, compared to the ocean, the atmosphere is relatively small in mass, so human-induced changes can affect it dramatically.
CO2 is the major cause of global warming
Global warming is caused by the emission of greenhouse gases . 72% of the totally emitted greenhouse gases is carbon dioxide (CO2), 18% Methane and 9% Nitrous oxide (NOx). Carbon dioxide emissions therefore are the most important cause of global warming.
Recent investigations have shown that inconceivable catastrophic changes in the environment will take place if the global temperatures increase by more than 2° C (3.6° F). A warming of 2° C (3.6° F) corresponds to a carbon dioxide (CO2) concentration of about 450 ppm (parts per million) in the atmosphere.
Methane's Role in Global warming Underestimated
By Dan Vergano, USA TODAY
Greenhouse gas calculations blame carbon dioxide too much for global warming, and methane too little, suggest researchers Thursday.
In the journal Science, a team led by Drew Shindell of the NASA Goddard Institute for Space Studies in New York finds that chemical interactions between greenhouse gases other than carbon dioxide cause more global warming than previously estimated by the Intergovernmental Panel on Climate Change and other efforts.
"The total amount of warming doesn't change, just the balance of gasses behind it," Shindell says.
The world's climate warmed an average about 1.3 degrees Fahrenheit from 1906 to 2005, very likely due to industrial greenhouse gases, the IPCC concluded in 2007, adding that carbon dioxide is "most important" greenhouse gas. Methane is a greenhouse gas produced by lanfills, agriculture and some industries.
In the study, Shindell and colleagues added chemical interactions between aerosols and greenhouse gases such as methane and carbon monoxide to a century-long model of climate change. They wanted to see the effects on each gas's "Global Warming Potential," or individual contribution to global warming.
Methane played a bigger role than expected, suggesting that climate treaties such as the 1997 Kyoto Protocol need to consider it more carefully, the study says.
Greenhouse gases are transparent to sunlight, but retain heat in the atmosphere, raising global average temperatures. Burning fossil fuels, deforestation and other human activities have raised greenhouse gas levels to historic values in the last three centuries.
"There is no way, other than aggressive geoengineering, to come close to meeting the world leaders? goal of overall warming not exceeding (3.6 degrees Fahrenheit) above preindustrial (levels) without focusing on BOTH carbon dioxide and non-carbon dioxide emissions," says Michael MacCracken of the Climate Institute, by email. "This is not an either-or choice — we must do both to have any chance at all."
Because non-carbon dioxide gasses also cause air pollution, MacCracken and Shindell both suggest that politicians may embrace limiting those emissions in developing nations more quickly than carbon dioxide ones. China has about 750,000 air-quality-related deaths annually according to the World Health Organization, for example.
In December, representatives of 192 nations head to Copenhagen to work on an international agreement to limit emissions. On the international front, "getting priorities right on the non-carbon dioxide greenhouse gases has some real value," says MacCracken, a former Clinton-administration climate scientist. If negotiations keep stalling on carbon dioxide emissions debate, then "all of our efforts on the non-carbon dioxide greenhouse gases won?t make much difference," he says. "There needs to be a deal and, in my view, cutting non-carbon dioxide greenhouse gases and soot can be a helpful bridge to getting an agreement."
Current emissions of aerosols actually cool the atmosphere an average about 1.26 degrees Fahrenheit, notes aerosol expert Joyce Penner of the University of Michigan. "So changing aerosol concentrations through changing greenhouse gas emissions is certainly a factor that needs to be considered," Penner says." I think that what is needed here is a holistic approach to climate control that takes into account all the factors that influence climate change (including the present day "protection" by aerosol emissions)." - source from usatoday.com
