Overview - Facts

Climate change is real. This fact cannot be disputed by scientific data. Nonetheless, there are those who believe that climate change is affected less by humans and more by natural processes. Regardless of one's personal belief, numerous facts indicate that human action does contribute to global warming. This Web page lists compiled facts and links to Web sites that provide these data.

The United States - In 2006 reports indicated that the US was the world's largest polluter. Although Americans make up just 4 percent of the world's population, they produced over 20 percent of the world carbon dioxide pollution (2007 EPA Report). Due to rapid growth in China, some reports indicate that China has recently surpassed the US as the world's largest polluter.

Rising Temperatures - Over the past 50 years, the average global temperature has increased at the fastest rate in recorded history. Scientists say that unless global warming emissions are curbed, average U.S. temperatures could be 3 to 9 degrees higher by the end of the century. (ClimateCrisis.org and Natural Resource Defense Council).

• The 10 hottest years on record have all occurred since 1990.
• Every year from 1998 through 2006 ranks among the top 25 warmest years on record for the United States - an unprecedented occurrence, according to the National Oceanic & Atmospheric Association (National Oceanic & Atmospheric Association).
• Global warming-related deaths are expected to double in just 25 years -- to 300,000 people per year.

Water shortages - In 2000, 31 countries with a collective population of half a billion people were experiencing chronic water shortages (New Internationalist). Global warming can lead to water shortages because more water molecules evaporate and are suspended in the air. This evaporation also leads to increased concentration of pollutants in water.

• By 2025, water shortages may affect 3 billion people in 50 countries
• Nearly half the world’s major rivers are going dry or are badly polluted. In China, 80 percent of the major rivers are so degraded they no longer support fish life.

The Polar Ice Cap - NASA scientists have found that the polar ice cap is melting at the rate of 9 percent per decade. Arctic ice thickness has declined by 40 percent since 1965. (Natural Resource Defense Council)

• At the current rate of retreat, all of the glaciers in Glacier National Park will be gone by 2070
• According to the National Snow and Ice Data Center, the extent of Arctic sea ice was at an all-time record low in September 2007, with almost half a million square miles of less ice than the previous record set in September 2005.

Storm Intensity - The surfaces of most tropical oceans have warmed by 0.25-0.5 degrees Celsius during the past several decades. A slight increase in ocean surface temperature can dramatically intensify coastal storms. (National Oceanic & Atmospheric Association and ClimateCrisis.org)

• The National Oceanic & Atmospheric Association (NOAA) projects that when sea surface temperatures increase by one degree Celsius, there is a three to five percent increase in wind speeds.
• The number of Category 4 and 5 hurricanes has greatly increased over the past 35 years.

Changes in Sea Level - Global sea level has already risen by four to eight inches in the past century, and the pace of sea level rise appears to be accelerating (Natural Resource Defense Council).

• The Intergovernmental Panel on Climate Change (IPCC) predicts that sea levels could rise 10 to 23 inches by 2100. In recent years, sea levels have been rising faster than the upper end of the range predicted by the IPCC.
• Greenland holds 10 percent of the total global ice mass; if it melts, sea levels could increase by up to 21 feet. In the 1990s, the Greenland ice mass remained stable, but the ice sheet has increasingly declined in recent years.

Threat to Species - The first comprehensive assessment of the extinction risk from global warming found that more than one million species could be committed to extinction by 2050 if global warming pollution is not curtailed (Natural Resource Defense Council).

• A recent study of nearly 2,000 species of plants and animals discovered movement toward the poles at an average rate of 3.8 miles per decade.
• Similarly, species in alpine areas appear to be moving vertically at a rate of 20 feet per decade in the second half of the 20th century.
• Polar bears are drowning because they have to swim longer distances to reach ice floes. The U.S. Geological Survey has predicted that two-thirds of the world's polar bear sub-populations will be extinct by mid-century due to melting of the Arctic ice cap.
• Scientists predict that a 3.6 degree Fahrenheit increase in temperature would wipe out 97 percent of the world's coral reefs.

Deforestation - The Earth’s forests absorb CO2, produce oxygen, anchor soils, moderate the climate, influence the water cycle and provide a rich habitat for millions of species of plants and animals (New Internationalist).

• Over half the world’s original forest cover has been destroyed in the last 45 years.
• More than 90 percent of forest loss is in the tropics.

Disease Infestation - In addition to the health risks associated with heat waves, flooding, wildfires, hurricanes, and other disasters affected by climate change, there is also great threat from infectious diseases like malaria and dengue fever (ClimateCrisis.org).

• Disease-carrying mosquitoes and rodents are spreading as climate shifts allow them to survive in formerly inhospitable areas.
• Malaria has spread to higher altitudes in places like the Colombian Andes, 7,000 feet above sea level.