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Greenhouse Gases More Page 10

Problems and Solutions

Although a lot of impact has already occurred, efforts to address climate change are underway. There are two approaches to the problem.
 
  1. The first is mitigation, which focuses on ways to prevent further global warming and associated climate changes by reducing the effects of human activities on land cover, atmospheric chemistry and other Earth system characteristics. However, due to the delayed response of the climate system to greenhouse gas and other anthropogenic forcings, much of the climate impact of 20th century activity has yet to manifest. As such, we can expect to see additional climate change even if we halt all land use and emissions.
     
  2. This leads to the second approach, which is adaptation, which focuses on living with observed and expected climate change and reducing the negative impacts to human and natural systems. These two approaches must be considered together in any global planning for planetary management. As suggested by the Union of Concerned scientists, it will be necessary to “Avoid the unmanageable so that we can manage the unavoidable.” Some efforts toward that end include emissions reductions through efficiency and carbon-free energy sources, and changes in agricultural practices.

Reservoirs - Fluxes - Global Warming Potential

Global Warming Potential (GWP) depends on the efficiency of a greenhouse gas molecule and its atmospheric lifetime. The global warming potential is measured relative to carbon dioxide and for a specific timescale. Recovery from the recent loading of the atmosphere with carbon dioxide will take tens of thousands of years. Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 72 over 20 years, 25 over 100 years and 7.6 over 500 years. The decrease in GWP at longer times is because methane is degraded to water and CO2 through chemical reactions in the atmosphere.

Remediation - Carbon Sequestration

There is an effort currently underway to capture smokestack greenhouse gases and sequester them in underground traps. The effort is further advanced in Europe than the United States. A more difficult problem is recovering the greenhouse gases already in the atmosphere.

Political Initiatives

The Kyoto Protocol of 2005 puts restrictions on certain greenhouse gas emissions and the Montreal Protocol puts restrictions on CFC emissions. In December 2009, the US Environmental Protection Agency declared that "greenhouse gases threaten the public health and welfare of the American people".