As we in the Northeast brace for Hurricane Irene, we are constantly being reminded by our newscasters that this may be a "big storm". Increased severe weather incidents are, of course, one of the long-term impacts of global warming. The frequency and intensity of severe weather may vary from year to year but inevitably as more heat energy stays within our atmosphere, this energy needs to be released at some point. Storms and tornadoes release this energy.
So what can be done about global warming? Is it already too late to prevent the worst case scenarios from occurring?
Let's start with the last question first. According to a 2009 MIT report, if little changes from the current situation - i.e., same emissions pattern as today, we can expect a 5 to 7 degree Centigrade (9 to 16 degree Fahrenheit) rise in global temperature by the end of this century. The results would be absolutely disastrous. Sea levels would be 20 feet above where they are now causing widespread destruction to some of the world's largest cities and most beautiful coastlines. In addition, a greater portion of the world will become unsuitable for crops because of temperature increases, increased desertification in some areas, and increased crop loss caused by storms and floods in others. The result: up to 3 billion people will have to migrate from the increased drier, warmer regions or starve. And this is the scenario for GHG emission patterns getting no worse than today. Higher emissions are a significant possibility as more developing nations achieve higher standards of living and the corresponding increase in energy use.
If you want to think shorter term - say to 2050, then just halve the numbers above - it's still a global disaster.
What can be done to prevent this disaster in the 40 to 90 years we have before it hits? Well, we have three tools at our disposal:
(1) Reduce greenhouse gas emissions
(2) Increase the "sinks" that can trap carbon dioxide and other GHG's
(3) Use engineering and technology solutions to protect coastal cities, food supply and the shoreline
(Note to certain budget-cutting Republican presidential candidates and their supporters: shutting down the EPA as you have been suggesting will not help the situation. I've left it off the list. Call me if you'd like to discuss further.)
The primary action we can take is to reduce greenhouse gas emissions and the rest of today's blog will discuss this subject. Reducing emissions has been the focus of the climate change conferences held over the past 15 years or so. It has been estimated that, to stabilize the climate, the nations of the world must reduce their GHG emissions by 50% from 1990 levels by 2050.
In the US, 94 to 95% of CO2 emissions come from the combustion of fossil fuels. Of this, 42% of the emissions come from electricity generation and 33% from transportation. Any plan to reduce US CO2 emissions should concentrate on these.
Coal for electricity production is a major source of emissions. As GHG emitters go, it is the worst. Natural gas used for electricty generation emits about half the amount of CO2 per kilowatt as coal does. So replacing coal plants with natural gas plants would go a long way to reducing the amount of CO2 the country releases. Alternative electricity generation sources that emit zero CO2 such as wind, solar, hydro and even nuclear must be considered. This conversion of course will take time and should be started now.
More efficient automobiles, trucks and busses combined with improved rail and mass transit projects offer a way to get at transportation, the second major source in the US. Mandatory increases in the fuel efficency of automobiles is essential. Fuel cell technology and hybrids that generate their own electricity may help as would using natural gas instead of gasoline and diesel. Two notes: (1) ethanol does not reduce the amount of CO2 emissions and we are basically converting food into fuel; (2) smarter management of the energy grid and the power plant conversion described above are essential if plug-in electric cars are ever expected to help. Gasoline emits CO2 in amounts about midway between natural gas and coal. So if we are just replacing gasoline with coal as the ultimate source of transportation energy, we will do little to solve the GHG problem.
To be continued and concluded in the next blog
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