By Jessica Helm
The average global temperature has increased by 0.5 degrees Celsius from 20 years ago. The amount of CO2 in the atmosphere has increased by about 10 percent over the same time. (See graph.) Sea levels have risen by about 5cm. Although .5C and 5cm changes sound insignificant (and are small compared to predicted future changes), they result in larger changes happening every day all over the world. You have seen the news: glaciers melting in our national parks, snow caps disappearing on mountains, large chunks breaking off glaciers and ice shelves as these bodies break apart. Artic permafrost is thawing, and polar bears populations are decreasing with the ice. The balance of ecosystems is changing as animal and plant species breed and bloom earlier in the spring and shift their geographic ranges with changing climate.
The primary source of these changes is the increasing concentration of greenhouse gases like CO2, methane, and fluorocarbon refrigerants (like Freon). The gasses insulate the planet and prevent the sun’s energy from being reradiated away from earth, resulting in a few degrees of warming of the planet. Carbon dioxide causes 62% of radiative warming, and refrigerant molecules, though low in number, have 20,000 times the insulating effect of CO2.
Most (80 percent) of the past 40 years warming is estimated to have gone to warm the oceans, causing the water to expand and sea levels to rise. Along the New York coast the sea level has risen about 2.7 cm in the last ten years, and could conservatively add another 10 cm in 20 years. Furthermore, Greenland and Antarctica are covered with thick layers of ice which are rapidly melting in places. It is not known how much of this ice will melt, but melting will certainly increase the rate of sea level rise.
Low lying areas like Long Island's south shore will be most affected, as shoreline is submerged and salt water floods estuaries and basements. The warming of the oceans will have a further unpredictable effect on the ocean currents which affect climate across the globe.
Rising air temperatures increase the amount of water vapor the air can carry, and this combined with other effects, such as altered ocean currents, is predicted to result in more frequent severe weather events such as hurricanes and droughts. Our entire climate is likely being affected by this mechanism, though no individual events can ever be definitely linked to global warming.
The science of climate change is full of uncertainty, due to multiple factors changing simultaneously. However, there really is no serious scientific debate remaining about climate change: a recent survey of published scientific papers on global climate showed that the consensus is clear and unopposed. The world’s climate is warming, and this is due at least in part and possibly entirely to human activity. It’s time to start reducing our CO2 footprint worldwide.
Where to Begin? The Long Island Group kicks off a Cool Cities Campaign this summer to reduce emissions one municipality at a time across Long Island. For details and to get involved, see the article on page 5, and contact Neill Clenaghan. Save money and reduce your own CO2 footprint. Find ways of using less fuel and less electricity: buy fluorescent lights, and replace old air conditioners and refrigerators with energy star appliances. Look into hybrid vehicles or using mass transit. Get a home energy audit to see if you can reduce your heating bills. Reference the web sites listed on page 7 for some ideas. It’s your money and your planet.