Understanding Global Warming and Its Impact

Global Warming

• 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.

Greenhouse Gas Emissions

• 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

Greenhouse Effect

• 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.

Global Warming: Causes and Effects

• 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)

Global Warming and Agriculture

• 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

Melting Glaciers and Pest Infestation

• Global warming directly results in the melting of glaciers.
• Warmer global temperatures also trigger increased pest infestations.

Impact on Agriculture

• 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).

Annual Greenhouse Gas Emissions by Sector

• 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%