Understanding Global Warming and Its Impact

Study Notes

Defined as the increase in Earth's average temperature
Leading to more frequent disasters like hurricanes, droughts, and floods
Average temperature rise over the last 100 years: slightly less than 1° Celsius (0.74 ± 0.18°C) or 1.3 ± 0.32° Fahrenheit
Linked to conspicuous increases in storms, floods, and forest fires over the past ten years
Current warming is rapid, unlike previous natural climate changes (Ice Ages and warm periods) which occurred over 50,000-100,000 years
The current rate of warming, over the past 30 years, is unprecedented according to scientists
Earth should typically be in a cooling phase based on natural cycles of solar and volcanic activity.

Despite efforts, the world is releasing more CO2 than ever before
Current CO2 levels are 385 parts per million (ppm) above historical levels of the last 800,000 years
NASA climatologist James Hansen emphasizes the need to reduce CO2 levels to a maximum of 350ppm

Global warming is the most critical environmental issue today
Human activities (like burning fossil fuels) increase greenhouse gases in the atmosphere
Changing the atmosphere's composition and contributing to global warming.
Climate scientists agree that human activities cause this problem.

Earth's temperature has risen about 1° Fahrenheit in the last century, largely attributed to human activity
Greenhouse gases (from burning fossil fuels like coal, natural gas, or oil) trap heat, causing temperatures to rise
The United States was responsible for 20% of global greenhouse gas emissions in 1997.
Global sea levels have risen 4-8 inches over the past century.
Impacts include damaging storms, droughts, increased mosquito-borne diseases, and more intense weather events (hot summers and intense thunderstorms)

Impacts of global warming on agriculture include significant effects like:
Loss of biodiversity (especially in tropical forests)
Loss of fertile coastal lands due to rising sea levels
Increased frequency of weather extremes (storms, floods, droughts)
Increased unpredictability of farming conditions
Negative shifts in distribution and amounts of fish/seafood
Increase in pests/diseases
Potential for extreme fluctuations/changes in weather patterns to cause drops in agricultural production and force farmers to change practices

Climate change threatens grain production, causing poverty
Warmer temperatures affect the growing season, impacting yields.
The presence of increasing levels of atmospheric carbon dioxide affects growth
Additional effects on quality of crops and agricultural areas (erosion, fertility, pests/diseases, glacier retreat).
Unusual events (El Niño Southern Oscillation effects).

Industrial processes are the largest contributors (16.8%)
Transportation fuel use is significant (14%)
Agriculture (12.5%) plays a major role
Other sectors like electricity generation (power stations), waste disposal and treatment, and land use contribute
Carbon Dioxide is the main greenhouse gas, making up 72% of total emissions; methane comprises 18%, and nitrous oxide 9%