Global Warming

By Aayush Gala

What is global warming?Global warming is the rise in the average temperature of Earth's atmosphere and oceans. Since the early 20th century, Earth's average surface temperature has increased by about 0.8 °C with about two-thirds of the increase occurring since 1980. Warming of the climate system is definite. Scientists are more than certain that it is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation. These findings are recognized by the national science academies of all major industrialized nations. Its projected to continue.

Greenhouse Effect• The greenhouse effect is a process by which

thermal radiation from a Earth’s surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since a part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.

• Some greenhouse gases are: Water vapour, Carbon Dioxide, Methane, Nitrous Oxide, Ozone, Chloroflorocarbons, Argon, etc

Details of some GHGs

• Carbon Dioxide (CO2) – Source: Fossil fuel burning, deforestation Anthropogenic increase: 30% Average atmospheric residence time: 500 years

Methane (CH4) – Source: Rice cultivation, cattle & sheep ranching, decay from

landfills, mining Anthropogenic increase: 145% Average atmospheric residence time: 7-10 years

Nitrous oxide (N2O) – Source: Industry and agriculture (fertilizers) Anthropogenic increase: 15% Average atmospheric residence time: 140-190 years

Some Pictures

Effects • Increase in temperature

• This century 2°C

• Raised sea level– 20-86cm

• More frequent extreme weather– More rain in extreme events– Hurricanes: >26°C

Health Effects Direct physical

heat

floods, droughts

Physicochemical

ozone

Biological

allergens

vector-borne disease

water-borne disease

food production, storage

Sociodemographic

population displacement

Alteration of vector induced infectious diseases – Malaria, Dengue- Seasonal distribution of Allergenic pollens, fungi- heat wave related deaths

Physicochemical effects Hydrocarbons + NOX

Ozone

Lung Inflammation

highertemperatures

Temperature Inversion

>32C UV

Allergen Sensitivity Respiratory disease

Severn Suzuki’s Speech in UN Earth Summit 1992, Rio de Janeiro

Solutions

• Conservation– Reduce energy needs– Recycling

• Alternate energy sources– Nuclear– Wind– Geothermal– Hydroelectric– Solar– Fusion