Evidence
1. Global Temperature Rise
2. Warming oceans
3. Shrinking ice sheets
4. Declining Arctic sea ice
5. Extreme events
The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.
Causes
Most climate scientists agree the main cause of the current global warming trend is human expansion of the "greenhouse effect"1 — warming that results when the atmosphere traps heat radiating from Earth toward space. Certain gases in the atmosphere block heat from escaping. Long-lived gases that remain semi-permanently in the atmosphere and do not respond physically or chemically to changes in temperature are described as "forcing" climate change. Gases, such as water vapor, which respond physically or chemically to changes in temperature are seen as "feedbacks."
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Effects
1. Change will continue through this century and beyond.
2. Frost-free season will lengthen.
3. Changes in precipitation patterns.
4. More droughts and heat waves.
5. Hurricanes will become stronger and more intense.
6. Sea level will rise 1-4 feet by 2100.
7. Arctic likely to become ice-free.
Global climate change has already had observable effects on the environment. Glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner. Effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves.
Solutions
1. Government Resources.
2. Responding to Climate Change.
Responding to climate change involves two possible approaches: reducing and stabilizing the levels of heat-trapping greenhouse gases in the atmosphere (“mitigation”) and/or adapting to the climate change already in the pipeline (“adaptation”).
