Greenhouse Ameliorators

Introduction

Greenhouse ameliorators refers to approaches or compounds that are intended to reduce the warming of the atmosphere that is caused by the accumulation of greenhouse gases—gases that increase the retention of heat entering the atmosphere in the form of sunlight.

Greenhouse ameliorators can be direct, involving the alteration of the atmosphere. For example, one scenario that is still conceptual and not yet real involves the introduction of tiny particles into equatorial regions of the atmosphere. The particles, which would increase the reflection of sunlight out of that area of the atmosphere, would lessen the heating of the tropical atmosphere.

Other greenhouse ameliorators are indirect. Reducing the use of fossil fuels and increasing the use energy sources such as solar and wind power that do not emit greenhouse gases is one example.

The use of greenhouse ameliorators has been spurred by the recognition that human activities are an important influence on atmospheric warming.

Historical Background and Scientific Foundations

The term greenhouse ameliorators is derived from the greenhouse effect. The latter is the documented warming of the portions of the atmosphere called the troposphere and the stratosphere, as well as the immediate surface of Earth. The warming is being caused by interactions between sunlight entering the atmosphere, particles suspended in

the atmosphere, and gases that are dissolved in the atmosphere. The result of these interactions is that heat is hindered from leaving the atmosphere. The name of the effect refers to the warming of the air in a greenhouse when sunlight is restricted from reflecting back out through the glass enclosure.

The overwhelming scientific consensus is that, beginning in the mid-eighteenth century when industrialization increased, gases (including carbon dioxide, methane, and nitrous oxide) began to accumulate in the atmosphere. These so-called greenhouse gases trap the heat of the sun, restricting its exit from the atmosphere into space.

Greenhouse gases can persist in the atmosphere for decades to centuries. Thus, even if all greenhouse gas production were to cease, the atmosphere could continue to warm for an undetermined period of time. However, eventually the warming would slow and perhaps even reverse.

There are two greenhouse amelioration strategies. The first tries to reduce the amount of greenhouse gases escaping to the atmosphere by reducing energy use and using sources of energy that are less likely to generate the gases. Examples of this strategy include the use of hybrid vehicles that are electrically operated some of the time, using more recycled materials rather than original materials in daily life, and using energy sources that do not involve the burning of fossil fuels.

The second amelioration approach adds compounds to the atmosphere or on Earth's surface that act to reduce the retention of the sun's heat. One example is known as agroforestry—establishing forests to soak up carbon dioxide from the air (in the language of climate change, forests are described as being carbon sinks). As of 2008, research is also being done in Japan and the United States to investigate the feasibility of trapping carbon dioxide released from the chimneys of coal-burning facilities, converting the gas to a liquid, and pumping the liquid deep underground or to the bottom of the ocean.

Other examples of the alteration of the atmosphere that are still conceptual include spreading material on the ocean surface that increases the reflection of sunlight, seeding the atmosphere to increase the formation of light reflecting clouds, adding food sources to the ocean to promote the growth of plankton that would absorb carbon and transport it to the ocean floor when they die, and introducing tiny light-reflecting particles into the atmosphere.

Impacts and Issues

The need for greenhouse amelioration is real. According to the Fourth Assessment Report released in 2007 by the United Nation's Intergovernmental Panel on Climate Change (IPCC), the evidence for the warming of Earth's climate is “unequivocal,” with human activities responsible for the marked increase in greenhouse gases since the year 1750.

Attempts to reduce the volume of greenhouse gases reaching the atmosphere go to the individual level. Driving more fuel-efficient cars and using energy sources such as wind and solar power can be productive and economical. Seeking alternate energy sources also goes to the national level, with governments of developed countries undertaking projects to establish wind and solar farms— facilities containing many wind turbines or solar panels to generate considerable quantities of electricity.

WORDS TO KNOW

AGROFORESTRY: The practice of sustainably combining forestry with agriculture by combining trees with shrubs, crops, or livestock. Two forms of agroforestry are alley cropping (strips of crops alternating with strips of woodland) and silvopasture (pasturing grazing livestock under widely spaced trees). Benefits include greater soil retention, biodiversity encouragement, higher monetary returns per acre, and more diverse product marketing.

FOSSIL FUELS: Fuels formed by biological processes and transformed into solid or fluid minerals over geological time. Fossil fuels include coal, petroleum, and natural gas. Fossil fuels are non-renewable on the timescale of human civilization, because their natural replenishment would take many millions of years.

KYOTO PROTOCOL: Extension in 1997 of the 1992 United Nations Framework Convention on Climate Change (UNFCCC), an international treaty signed by almost all countries with the goal of mitigating climate change. The United States, as of early 2008, was the only industrialized country to have not ratified the Kyoto Protocol, which is due to be replaced by an improved and updated agreement starting in 2012.

PLANKTON: Floating animal and plant life.

STRATOSPHERE: The region of Earth's atmosphere ranging between about 9 and 30 mi (15 and 50 km) above Earth's surface.

TROPOSPHERE: The lowest layer of Earth's atmosphere, ranging to an altitude of about 9 mi (15 km) above Earth's surface.

Such efforts are supported by most people, although opposition to the noise and claimed adverse health affects of the low frequency sound emitted by wind turbines has been raised by those living nearby. Other alternative energy sources such as nuclear power are more controversial.

Despite the present efforts, more needs to be done if the greenhouse effect is to be halted or reversed, according to the IPCC. Hindering this is the economic disparity between developed and developing nations, which makes amelioration efforts by poorer countries harder, and the reluctance of some developed nations to implement international amelioration plans such as the Kyoto Protocol. For example, Canada, which signed the Kyoto Protocol and supported the protocol in past federal governments, began to distance itself from the agreement as of 2007, arguing that the amelioration targets are unattainable and would result in an economic disadvantage to the country. The United States and Australia opted not to ratify the protocol initially, but Australia announced it would in December 2007.

See Also Abrupt Climate Change; Atmospheric Structure; Climate Change; Infectious Disease and Climate Change.

BIBLIOGRAPHY

Books

Hillman, Mayer, Tina Fawcett, and Sudhir Chella Rajan. The Suicidal Planet: How to Prevent Global Climate Catastrophe. New York: Thomas Dunne Books, 2007.

Lovelock, James. The Revenge of Gaia: Earth's Climate Crisis and the Fate of Humanity. New York: Perseus Books, 2007.

Periodicals

Flemming, James R. “The Climate Engineers.” The Wilson Quarterly (Spring 2007).

Web Sites

“Climate Engineering Is Doable, as Long as We Never Stop.” Wired, July 25, 2007. < http://www.wired.com/science/planetearth/news/2007/07/geoengineering> (accessed November 10, 2007).