The Greenhouse (A)ffect(s you)
December 3, 2009
It works like this:
www.byronenvironmentcentre.asn.au/climate.htm
I. Solar radiation that makes it through the atmosphere is absorbed by the earth’s surface.
II. As a result, the earth’s surface emits heat as infrared radiation.
III. This longwave infrared radiation wafts up into the atmosphere, and is absorbed by a number of gases dubbed greenhouse gases.
IV. The absorption of radiation by GHGs causes the atmosphere to warm up.
The greenhouse effect is not bad in itself; we can thank this force of nature for the fact our bums are not frozen through and through. But the concern is that in recent years human contribution to levels of atmospheric gases is on the rise – significantly, meaning the earth is beginning to warm up. To be sure, the difference seems minimal, but the effects are wide-ranging.
According to the EIA, ”Levels of several important greenhouse gases have increased by about 40% since large-scale industrialization began around 150 years ago.” Additionally, the same article goes on to cite the IPCC in that over the last century global mean temperatures have risen between 1.1° and 1.6°F. Quoting the IPCC’s Fourth Assessment Report (Summary for Policymakers):
Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.
So, that’s that. I don’t want this blog to delve too deeply off the intended topic, but I’d also like to briefly cover the basic GHGs.
CO2: Produced naturally in animal respiration, but is also released in the burning of fossil fuels and deforestation. It accounts for 60% of the enhanced greenhouse effect.
Methane: Methane (CH4), though not as readily occuring as CO2, is much more potent. Produced by some kinds of bacteria, it is also created in rice farms, and burped by cows and other cattle. One cow emits a ½ lb. of CH4 a day.
NO2: Nitrous oxide (NO2) is emitted by bacteria in the soils, but atmospheric levels have risen primarily due to the use of nitrogen-based fertilizers, and also, sewage treatment.
CFCs: Chlorofluorocarbons (CFCs) were used as refrigerants, but were found to wreak havoc in the earth’s ozone layer by breaking down O3. CFCs were replaced by safer hydrofluorocarbons (HFCs), which while not damaging the ozone layer, do trap heat and are thus considered a GHG.
Various effects of increased GHGs are:
Watery
- As water can expand at warmer temperatures, sea levels will continue to rise. Sea levels are currently rising at 1/10 in/yr.
- Rising sea levels can result in increased flooding, including cities and even entire islands. The Majuro Atoll , part of the Marshall Islands, is expected to lose 80% of its land with a 20-inch rise in sea level.
- A rise in sea levels will also have an impact on coastal ecosystems; in the U.S., a one-foot rise will mean a 17-43% loss in wetlands.
- Other problems created by rising sea levels include coastal erosion, intensified storms, an increase in coral bleaching due to such storms, and also a loss of available fresh water to coastal cities.
- Similarly, water resources in general will be diminished due to melting mountain glaciers, which provide fresh water to wide area. For example, the Colorado River waters much of the western U.S. and is fed by mountain glaciers.
- Glaciers in general are melting, which can pose a number of problems but namely a rise in sea levels.
- Disappearing ice packs will also affect the folks who rely on them to hunt seals and walruses. Seals also use ice packs to raise their young.
Wild
- A rise in temperatures will mean warmer winters and hotter summers. Winter can usually be relied upon to slow the growth of germs and diseases; warmer, wetter winters will allow such organisms to spread like never before. Hotter summers would be a bummer in general, but combined with increased flooding they would also allow diseases to spread more quickly. Warmer weather year-round would mean mosquitoes and other disease-packing pests to spread like wildfire.
Nasty
- Higher levels of C02 can spur growth of weeds such as ragweed, the pollen of which is an allergen.
- Heat waves can claim lives; in 2003, extreme heat waves across Europe cost 52,000 lives.
Animals die
– An increase in CO2 means more of it gets absorbed by the oceans, leading to increased acidification. An estimated 500 billion tons has been ocean-absorbed since the start of the Industrial revolution…
Pteropod (water column snail)
- …which results in the deaths of marine life, such as pteropods (sea snails), which are important part of the polar food chain.
- Acidification can also kill off planktonic plants and animals, the bottom of many food chains. It also been predicted that populations of shellfish may die out from the increased CO2 . Acidification also weakens coral reefs, which may be too be brittle to withstand the ocean waves.
- Phytoplankton, which provide much of the earth’s oxygen, thrive in cooler oceans; warmer seawater may result in a decrease in phytoplankton. Algae is also disappearing, as it is more difficult for nutrients to rise in warmer water.
- Trout and salmon are adapted to streams 50-65o C. The predicted rise in temperatures in those streams is estimated to lead to a habitat loss as high as 17% by 2030, 34% by 2060 and 42% percent by 2090.
It should also be noted that some of the effects I’ve listed aren’t caused by global warming per se, but increased CO2 levels, which as a trend is pretty much unquestioned, and is directly linked to the burning of fossil fuels. Alternative energies, by design and intent, don’t release CO2 or GHGs.
