Atmospheric Climate Change & Global Warming Primer

The Inter-Governmental Panel on Climate Change ( IPCC ) Report concludes that:

• Globally averaged surface temperatures have increased by 0.6 ± 0.2 °C over the 20 th century.
• Surface air temperature is projected to warm 1.4 to 5.8 0 °C by 2100 relative to 1990.
• Globally averaged sea level is projected by models to rise 0.09 to 0.88 m by 2100.

Climate Change has been called one of the most serious long-term threats to human society. Unfortunately, because of the complex environmental, scientific, and socio-economic factors relating to climate change, solutions and actions have been minimal compared to the immense challenges.

Natural Sources of Climate Change

Natural sources of climate change include: volcanic activity, solar flares, changes in earth’s orbit and continental drift.

Mount St. Helen, May 18, 1980 eruption.

The Natural Greenhouse Effect

Solar Radiation

The Earth’s atmosphere contains naturally occurring “Greenhouse Gases” (GHGs) such as water vapour, carbon dioxide, ozone (CO₂), methane (MH₄), and nitrous oxides (N₂O), as well as human-made (anthropogenic) greenhouse gases.

These gases are relatively transparent to incoming short wave solar radiation, but they do absorb the re-radiated long-wave energy and heat up Earth’s atmosphere. This results in the natural “Greenhouse Effect” that insulates Earth from heat loss.

Without this natural greenhouse effect, the average temperature of Earth’s surface would be 33 °C colder than the present 15 °C. This is a naturally occurring phenomenon, in a delicate balance.