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Earth is surrounded by a layer of gases called greenhouse gases. Greenhouse gases include carbon dioxide, water vapor, methane, and several other gases. Many of these occur naturally, but human activity contributes considerably to the amount of greenhouse gases in the atmosphere.
As the Sun's rays reach Earth, they pass through this layer of gases to the surface of the planet. This warms the planet up. The ground then reflects these rays back as infrared (thermal radiation). Some of these infrared rays do not pass through the greenhouse gases layer and are reflected back to the ground, thus warming it up. This is called the greenhouse effect. This is very much how a classic greenhouse works. Made of glass, the greenhouse gas allows light to pass through but prevents the heat from being reflected back, thus warming the plants inside.
This ability to trap heat energy, much like a classic greenhouse, is why these gases are called greenhouse gases. This phenomenon is essential for life on earth. Without this layer of gases surrounding the planet, it would be a completely inhospitable place to live in. Life has thrived on earth due to the effect of this layer.
Greenhouse Gases Emissions
However, as many would say, too much of a good thing is bad. Human activities have increased the thickness of this layer. This, in turn, is causing the planet to warm up. Observations show that the temperature of the planet rose by 0.6C over the 20th century. The latest report from the Intergovernmental Panel on Climate Change (IPCC), released February 2006, states that the probability that this increase is attributed to human activity is 90 percent.
This increase in the thickness of the greenhouse gas layer is happening at a speed never witnessed before, trapping more energy than ever. This is what scientists call the enhanced greenhouse effect.
Apart from water vapor, nearly all the other greenhouse gases are increasing due to human activities. The main greenhouse gas is carbon dioxide (CO2). This is produced mainly from the burning of fossil fuels (coal, petroleum, and natural gas) as well as the cutting down of forests. Methane, another greenhouse gas, is produced from agricultural activities, change in land use, and garbage wastes. While it has a much smaller percentage in the atmosphere, methane is ten times more potent than CO2 as a greenhouse gas.
So What Is the Big Deal?
Many people, especially those living in northern colder areas, would regard this warming effect as a good change. However, it could have disastrous effects on their lifestyles. Besides, other people in other parts of the world would be adversely affected.
Determining the exact effects of climate change is very hard, if not impossible. This is due to the fact that the climate system is extremely complex. Temperature rise is not the only thing to be monitored. Changes in snow, ice caps, the oceans, water vapor, and clouds must also be taken into account. These factors could amplify the effects of climate change drastically. Climate models exist that try to take in account as many of the different variables as possible to try and project more accurate expectations of the change in climate.
While climate models are not crystal balls telling us the future, they are the most accurate option we currently have. These models are so expensive to run and to interpret that only a handful are made each year in order to maximize their accuracy.
Climate change is blamed by most scientists for drastic climatic conditions that have plagued earth lately. The increase in tornadoes, hurricanes, and tsunamis is attributed to climate change.
Climate change is expected to increase heat waves, leading to hotter and drier summers. This could lead to great stress to humans and livestock as well as increasing forest fires and increasing the pressure on water supplies. It could also damage crops in the warmer areas of the world. A heat wave that struck Europe in 2003 resulted in a health crisis, led to the death of at least 35,000 people, and caused the destruction of thousands of acres of crops.
More intense rainfalls will also increase the probability of floods. Floods, besides causing death to thousands of people every year, contribute to soil erosion and crop destruction. On the other hand, other regions will be hit with severe droughts.
The rise in temperature will also add to food insecurity around the world. With the loss of crops, the floods, and the increased stress on fresh water sources, a health crisis could be in store for the poorer nations of the world. Some diseases will also spread easier due to the warmer weather. Mosquitoes, for example, will reproduce and spread more with the rise of temperature, spreading diseases they carry to even more people, such as malaria. Warmer weather can lead to an increase in the rodent and flea populations, spreading plague further in Africa. The West Nile virus, never seen outside of Africa seven years ago, has reached as far as Canada. It has infected over 21,000 people and killed more than 800 of them in North America.
Higher temperatures will cause the ice caps to start melting. This will lead to rising sea levels. The United Nations Framework Convention on Climate Change (UNFCCC) claims that the global water level has risen by about 10–20 cm over the past 100 years. This is over 10 times the rate of increase that has been taking place in the past 3,000 years. Most climate models predict even faster sea-level rises till 2100. Small islands are especially in danger of disappearing under the rising water, while coastal cities risk major destruction due to huge waves and floods.
Vulnerability
Sadly, the people that will be most affected by climate change are the poorest people in the world. These people, ironically, are the least contributors to the problem, yet they will take the heaviest brunt of it. Adverse health conditions, droughts, floods, and famines are some of the problems they will face due to climate change.
Even if people act now, there is no way to reverse the effects of climate change. This is because there is always a time lag when dealing with greenhouse gases: They can stay in the atmosphere for tens of years. However, acting now will enable us to mitigate and even prevent some of the more adverse effects. Therefore, while taking action to reduce emissions is important, this must be coupled with mitigation and adaptation programs.
The time to act is not too late if communities, politicians, and businesses move now. Sadly many people around the world have been reluctant to take action, saying this may harm their economies.
However, a report released by British economist Sir Nicholas Stern in November 2006 focused on the economic implications of inactivity regarding climate change. The Stern Review stated that, if governments and businesses act now against climate change, the loss to global Gross Domestic Product (GDP) would be one percent by 2050. That means that the world would be one percent poorer than what it otherwise would have been by 2050. According to the report, however, doing nothing to stem climate change could lead to a permanent reduction in consumption per head of 20 percent.
To make the math simpler, taking action now will make the world one percent poorer by 2050; inaction would leave the world a fifth poorer than what it should be. In addition, the costs will not be divided equally. Once again, the poorer nations will bear the burden more.
Sir Nicholas Stern cited climate change as "the biggest market failure the world has ever seen." Scientists around the world have called it the greatest threat to life on earth. Not only our way of life but our very existence are threatened. Every living creature stands at risk.
While many people dismiss a rise of a few degrees in the temperature as nothing to worry about, we must remember that it was a change of 5C that brought about the ice age millions of years ago, most probably triggering the extinction of dinosaurs.
How will you act today?
Sources:
"Climate Change 2001: Impacts, Adaptation and Vulnerability", Chapter 10: Africa, 10.2.4. Human Health. UNEP/GRID-Arendal. Last accessed 7 Mar. 2007.
"Climate Change Drives Disease to New Territory", The Washington Post. 5 May 2006. Last accessed 7 Mar. 2007.
The Stern Review Report, Last accessed 7 Mar. 2007.
The UNFCCC Climate Change Information Kit, Last accessed 7 Mar. 2007.
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