Contributors to Accelerated Climate Change

Greenhouse gases - carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons - are building up in the environment, and the earth's climate is predicted to change as a result. Energy burned to power cars and trucks, heat homes and businesses, and run manufacturing plants is responsible for about 80% of global carbon dioxide emissions, about 25% of U.S. methane emissions, and about 20% of global nitrous oxide emissions.

Since the early 1800's, these human activities have helped to increase concentrations of carbon dioxide by 30%, and methane, a greenhouse gas with 22 times the global warming potential of carbon dioxide, by 140%. In 1994, the United States emitted about one-fifth of the total global greenhouse gases.

In Maine (1990) 19.2 million tons of carbon dioxide were released into the atmosphere from fossil fuel combustion. An additional 2.9 million tons were released from cement production, waste management, and agriculture. Transportation was the highest source of carbon dioxide emissions, contributing 47% of the annual total. Of the New England states, Maine has the highest per capita carbon dioxide emissions.

Current and Future Climatic Changes Worldwide and
in Maine

During the past century global temperatures have increased by more than one degree Fahrenheit and the sea level has risen about seven inches. In Lewiston, Maine, records indicate that the temperature has risen 3.4 degrees Fahrenheit over the past century. Along Maine's coast over the past 50 years the sea level has risen gradually at a historic rate of 2 mm/year.

The ten warmest years on record worldwide have been since 1983. Three of the last five years have been the warmest. Global temperature in 1998 was the hottest in the historical record and recent temperatures may have been the highest of the past millennium. Three different records of temperatures preserved in tree rings and elsewhere indicate that the extensive and abrupt, 20th-century warming is unique in the past 1000 years.

IPCC scientists project that temperatures could rise from 1.5 degrees to 4.5 degrees Centigrade over the next 100 years if carbon dioxide emissions double. They have estimated that the sea level may rise between six to 43 inches by the year 2100.

Projected consequences of global warming include: unusual weather patterns of heavy storms and heat waves resulting in flooding and droughts; seasonal variations, with spring already arriving earlier in many parts of the world and disrupting migration and reproduction patterns; threats to water supplies; as polar ice and glaciers melt, sea level rise and coastal flooding resulting in lost homes and habitat; spreading infectious diseases as warming temperatures enable mosquitoes to extend their ranges; and shifts in plant and animal ranges with some species' populations declining or becoming extinct.

Worldwide, the elderly, the young, the sick, and the poor - the most vulnerable members of the human race - and other species will be most susceptible to the consequences of global warming.

Specifically in Maine, extreme drought conditions and the warmest summer on record in 1999 and the ice storm of 1998 are symptoms of climate change. In the future, Maine's forest ecosytems, coastal areas, lakes and streams, agricultural output, and human health may be significantly impacted by global warming.

References: Climate Change and Maine, U.S. Environmental Protection Agency, September 1998; State of Maine Climate Change Action Plan, Maine State Planning Office and University of Maine, Spring 2000; Global Warming: Early Warning Signs, a map and references developed by Environmental Defense Fund, Natural Resources Council, Sierra Club, Union of Concerned Scientists, U.S. Public Interest Group, World Resources Institute, and World Wildlife Fund, 1999.