Combating Global Warming

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To slow down global warming, the concentration of greenhouse gases, carbon dioxide in particular, must be lowered. This can be best achieved by reducing fossil fuel combustion and converting to technologies that reduce the emission of harmful gases to the environment. In absence of adequate support for cutting emissions, we need to lower carbon dioxide levels in the atmosphere either by reducing the carbon in fuel (decarbonization) or by preventing carbon dioxide’s release into the atmospheric air by storing it in other mediums (sequestration).

Decarbonization can be accomplished by switching to alternative fuels with higher H/C ratios. Coal has no hydrogen, and is therefore considered to be the dirtiest of all fossil fuels. Natural gas has four hydrogen atoms for each carbon and is considered cleaner than other types of fossil fuels. Of course, the best option is to remove carbon altogether and use pure hydrogen as fuel. Hydrogen is, however, highly explosive and has a low density. Additionally, it must be kept at high pressure, which makes it even more dangerous. A good way of utilizing hydrogen is through fuel cells. Fuel cells are devices that combine hydrogen and oxygen in the air to produce electricity (Transportation). The only product is water vapor, which is not a pollutant.

Figure 1 Large amounts of carbon dioxide are trapped in vast forests and large bodies of water.
Figure 1 Large amounts of carbon dioxide are trapped in vast forests and large bodies of water.

Sequestration refers to the long-term storage of carbon underground or in oceans so as to prevent the buildup of carbon dioxide concentration in the atmosphere. Earth’s oceans have the capacity to hold 45 trillion tons of carbon - 60 times as much as the atmosphere. 2.4 trillion tons are contained within organic matter, such as trees and soil. Untapped fossil fuel reserves could add another 10 trillion tons (Savage, 2001). This means that the oceans alone can absorb all the carbon dioxide that will eventually be produced. However, there are problems with this scenario. As carbon dioxide dissolves in water, the water becomes more acidic. This could harm marine organisms, demonstrating that one environmental problem potentially leads to another equally important environmental problem.

Question: What would have happened if oceans could not dissolve the carbon dioxide in the atmosphere? Answer: The amount of carbon dioxide in atmospheric air is a tiny fraction of that dissolved in ocean. Without water the atmospheric carbon dioxide concentration would have been much higher, making the atmosphere much hotter and unsuitable for most forms of life. In fact, the planet Venus apparently retains much of its carbon dioxide in its atmosphere, keeping its surface temperature at a searing 470 C (880 F), today (See box “Venus”).

Carbon dioxide can also be sequestered by planting trees (Figure 1). Photosynthesis helps by removing carbon dioxide and converting it to carbohydrates and food (Biomass Energy). This also improves air quality and beautifies the landscape. Unfortunately, trends point in the opposite direction. In the last few decades, much of the existing rainforests have been lost to logging and used as wood fuel or cut down to pave the way for urbanization. Another option is to inject the carbon dioxide back into coal mines, oil fields, and saline aquifers. This is being done to some extent in enhanced oil recovery and the reclamation of abandoned mines.

Other less serious approaches have been proposed in which fleets of aircraft crisscross the skies releasing dust into the low atmosphere, millions of hydrogen-filled aluminized balloons are sent into the sky, or thousands of mirrors are put into orbit, all in order to reflect sunlight back to space (Begley, 1991). We could adjust the numbers to balance cooling as a result of reduced insolation with increased heating from emissions of greenhouse gases.


The Kyoto Protocol

In response to growing concern and mounting evidence of global warming, the United Nations hosted the 1992 Earth Summit in Rio de Janeiro, Brazil, where leaders of most industrialized countries agreed to adopt policies aimed at protecting biodiversity. Gases specifically targeted were carbon dioxide, methane, sulfur hexafluoride, HFCs, and CFCs. Furthermore, the Rio agreement established a legal ground to protect a country’s biological assets by giving host countries the intellectual property rights on genetic information of their unique animals or plants. Unfortunately, because of the low price of petroleum and lack of enforcing authority, the use of fossil fuels and the emissions of carbon dioxide continued to increase.

The failure of the Rio Summit prompted many to organize a meeting in Kyoto, Japan in 1997. This meeting was to devise plans to fight climate changes and their adverse consequences on the world’s weather, agriculture, and ecosystems. Many countries favored putting limits on fossil fuel consumption, phasing out CFCs and other chlorine and bromine-based products, banning future deforestation and planting new trees, increasing efficiency, and promoting renewable energy sources. The United States argued against the measure and considered the protocol to be biased, unfair, and politically motivated. If ratified, it puts unfair strain on the US economy, while giving unfair advantages to countries that are not covered under this treaty, like China and India. There will be more incentive for US companies to transfer their manufacturing to these and other less-industrialized countries that are inherently less efficient and thus the greenhouse gas problem will actually worsen.

Developing nations opposed the US view, stating that the cost of cleanup should be borne solely by rich nations that had done the most damage over the past years and arguing that their fledgling economies should not pay the price for the petroleum-driven economic growth of developed nations. Specifically, most criticized the United States for being the biggest contributor to global warming. The US, with 5% of the world population, is responsible for one fifth of all carbon dioxide emissions. A compromise was finally reached, stipulating that by 2012, the so-called Annex 1 countries (the developed countries and the Eastern European countries of the former Soviet block) were to reduce their collective emissions to 5.2% below the 1990 benchmark. The non-Annex 1 countries would be exempt from these restrictions for a ten-year grace period. However, to induce other nations (notably China and India) to join the agreement, it required rich countries to establish funds to finance costs of replacing CFCs in poor countries by benign refrigerants. In addition, the protocol allowed the signatories to meet emission reduction requirements by devising an emission trading market, which allowed Annex-1 countries to receive emission credits for helping the non-Annex-1 countries reduce emissions. In order to be binding under international law, the treaty would need ratification by countries responsible for at least 55% of the global greenhouse gas emissions of 1990.

In 2001, the United States officially pulled out of the treaty, effectively making the treaty enforceable only if Russia, responsible for 17% of the greenhouse gases, ratified the treaty. In February 2005, after some modifications, Russia agreed to sign the treaty and Kyoto Treaty officially went into effect. Thirty five industrialized countries have signed a binding commitment to curb their greenhouse gas emissions by 2012 to overall levels that are 5.2% below 1990 levels. The European Union has committed itself to cut emissions by 8%, Japan and Canada by 6%, while Russia has agreed to limit emissions to 1990 levels. Developing countries are exempt from this protocol, although many have expressed a desire to sign on and are planning to reduce emissions voluntarily. Australia was the last country who signed the agreement, leaving the United States the only developed country who has not ratified the treaty.

By 2006, China had already overtaken the United States as far as total carbon dioxide emission. With China’s heavy reliance on coal for production of its massive amount of electricity, the situation is not getting any better soon. At the time of this writing China is producing 2.5 times greenhouse gases as it did in 1991 when Kyoto Protocol was initially drafted. India’s contribution has risen from 2.9% of the world emission in 1991 to 4.4% in 2008 (4).

Carbon Abatement Strategies

The major strategies used to meet the Kyoto benchmark are:

1. Emission Trading -- The establishment of an emission market where emission credits are traded. This way, companies and countries could continue producing pollutants as long as they could offset their higher emissions by buying credits from companies or countries that opted for cleaner technologies or deployed emission control strategies. The rationale for this option is that as long as the total emissions are reduced on a global scale, it does not matter where these reductions are made. US is the prime proponent of this approach.

2. Carbon Capture and Storage (CCS) -- This is the process by which the carbon dioxide produced at the power plant is captured and stored (sequestered) instead of being released into the atmosphere.

3. Carbon Tax -- Taxes are based on the amount of carbon emission per unit energy production (kg/kWh, or lb/Btu). This scheme is used in most European countries.

4. Renewable Resource Mix -- Proposed in Britain, electrical suppliers are obligated to acquire a certain fraction of their energy from renewable sources. The fraction is gradually increased until their obligations under Kyoto Treaty is met.


(1) Begley, S., “On the Wings of Icarus,” Environment, May 20, 1991.

(2) Energy Information Administration website,

(3) Savage, Neil, “Greenhouse Effects, R.I.P.,” Discover, August 2001.

(4) Toossi Reza, "Energy and the Environment:Sources, technologies, and impacts", Verve Publishers, 2005

Further Reading

Gore, A., An Inconvenient Truth, Penguin Books, 2007.

Roleff, T., Pollution: Opposing viewpoints, Greenhaven Press, 2000.

Walsh, P. J., Dudney, C. S., Copenhave, E. D., Indoor Air Quality, CRC Press, 1984.

Environmental Science and Technology, published by the American Chemical Society.

External Links

Environmental Protection Agency (

Occupational Safety and Health Administration (OSHA) (

Intergovernmental Panel on Climate Control (IPCC), (

United Nations Environment Programme (

World Health Organization (WHO) (