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About Climate Change and the Greenhouse Effect

Greenhouse gases, which include water vapor (H2O), ozone (O3), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N20), are able to absorb and re-emit infrared radiation, while not blocking visible light. The greenhouse effect occurs when solar radiation is absorbed by the earth’s surface, converted into heat, and subsequently emitted into the atmosphere as infrared radiation. Some of this infrared radiation escapes into outer space; however, some is absorbed and re-emitted back towards the earth’s surface by greenhouse gases. These returning waves of infrared radiation warm the troposphere and the earth,s surface once again.

Without the greenhouse effect the planet's mean temperature would be 60°F cooler and life on Earth as we know it would not be possible. In other words, the greenhouse effect is a naturally occurring phenomenon. Global warming, however, is the result of the 'enhanced' greenhouse effect. Human activities, such as deforestation and the combustion of fossil fuels, have tipped the delicate balance of greenhouse gases in the atmosphere, thereby intensifying the natural greenhouse effect. A recent publication by the Intergovernmental Panel on Climate Change (IPCC), entitled "Climate Change 2007:The Physical Science Basis, Summary for Policy Makers", finds that it is "very likely" that emissions of greenhouse gases from human activities have cause "most of the observed increase in globally averaged temperatures since the mid-20th century."

Globally, higher temperatures cause ocean water to expand and glaciers to melt causing sea levels to rise. Glaciers around the world have already begun to melt at startling rates. The coastal regions of the U.S. that are most vulnerable to higher sea levels are the mid-Atlantic and south Atlantic coasts and the Gulf Coast. Rising sea levels pose a number of serious threats to coastal regions including erosion of beaches, permanent inundation of wetlands and lowlands, increased flooding and storm damage, and salinization of fresh water reserves. The ecological and economic damage is expected to be enormous. More extreme weather events will likely result in billions of dollars worth of damage to coastal property and shipping infrastructure. Warmer ocean temperatures and the flooding of coastal wetlands, which provide habitat for numerous plant and animal species, could ruin coastal and marine ecosystems and cause valuable commercial fisheries to collapse.

Around the world, rising temperatures and changing patterns of precipitation will also impact agriculture, yet the exact nature of these impacts remains unclear. The production of some crops in some regions may increase due to a longer growing season and more frequent precipitation, while the production of other crops in other regions could fall significantly due to more frequent droughts.

We can also expect to see the effects of climate change on a local level. Though global warming is indeed a global issue, we must take action locally if we are to prevent any of the forecasted effects of climate change. In Williamstown, the Berkshires, and New England, global warming is predicted to negatively impact our famous fall foliage, as changing temperature and precipitation patterns affect growing seasons. The New England ski season, reliant on abundant snow and cold temperatures, could also be adversely impacted. The old, beloved sugar maples in Williamstown’s own Hopkins Memorial Forest, along with the entire maple sugar industry, will suffer as warmer nights prevent the sap from running; forest records already show a decline in the trees’ production.