It reduces the amount of short-wave radiation absorbed by the atmosphere, but may only be a partial solution.
One method of countering climate emergencies is to reduce the amount of short wavelength radiation the earth absorbs. The basic principles of short-wave climate engineering (SWCE) are associated with stopping heat energy reaching the surface of the earth, which is warmed principally by absorbing short-wave radiation, and cooled by emitting long-wave radiation. Variations in this balance, for example greenhouse gases preventing cooling by trapping long-wave radiation, can lead to a changing of earth’s temperature.
The basic aim of SWCE is to reduce the amount of short-wave radiation absorbed by reflecting more back into space before it reaches the surface.
Natural components of the earth’s surface and atmosphere already reflect around 30% of incident radiation. Simple calculations suggest an additional 1-2% reflected radiation would balance the heating effect of doubling carbon dioxide (CO2) concentrations. However, these ignore energy distribution within the climate system. Incoming short-wave and trapped outgoing long-wave energies have different spatial distributions, meaning the net impact of SWCE and increased anthropogenic greenhouse emissions would not be zero. Climate features such as regional temperatures and precipitation, seasonal variability and ecological productivity would be affected.
A variety of methods could be employed to reduce the flux of short-wave radiation hitting the earth’s surface. They include:
–increasing ocean surface reflectivity, for example using thin immiscible films across water surface or micro-bubbles;
–increasing the earth’s surface reflectivity, for example by altering land use and modifying crop distributions;
Read All Comments
–cloud whitening, which would increase the direct reflectivity of clouds through chemical alteration; and
–space mirrors, either launched to orbit the earth above the atmosphere, or positioned further away from the surface at the “Lagrange point.”
Reservations. The main concern associated with implementing climate engineering in the near future is uncertainty regarding a string of interlinked effects that artificially tampering with atmospheric processes potentially could initiate. Limited scientific research has been conducted because of a series of concerns many atmospheric scientists share:
–The climate system inherently might be too complex and the possibility of harmful side effects too large for intentional human intervention ever to be considered.
–Public perception of SWCE could be that it is a substitute for cutting emissions.
–If it were possible to control the climate through SWCE, the political question arises of who has international power to determine what the optimum global climate should be.
–There are ethical questions about humankind’s right to modify the earth’s climate.
Little currently is understood about the benefit or cost of reducing absorbed radiation and essentially nothing known about the net combined impacts of SWCE and elevated greenhouse gas concentrations in a wide range of environmental areas. This makes the short-term employment of any SWCE methods highly risky–especially those that propose to emit new gas phase species whose photolysis and atmospheric reactions are poorly understood. Unanticipated negative impacts on human and ecological systems currently could overshadow expected benefits.
Risk uncertainty. The most recent Intergovernmental Panel on Climate Change (IPCC) report concluded with high confidence that anthropogenic accumulation of greenhouse gases in the atmosphere is altering the Earth’s climate. However, there is no guarantee that the previously observed trend of gradually intensifying consequences will continue. For example, there is the possibility that non-linear feedbacks in the climate system could accelerate these impacts.
Given the long lifetime of CO2 in the atmosphere, even aggressive near-term mitigation efforts would take several decades to begin reducing global CO2 concentrations and the likelihood of their associated consequences. Therefore, if the effects of SWCE could be better understood it might be a viable option.
Verdict. SWCE represents a potential ‘part solution’ to averting the effects of human-induced climate change, though current understanding of the effects is insufficient to sanction immediate climate interventions. There are potential climate emergencies that SWCE could avert, but also other climate effects that will not respond to such engineering.
To read an extended version of this article, log on to Oxford Analytica’s Web site.
Oxford Analytica is an independent strategic-consulting firm drawing on a network of more than 1,000 scholar experts at Oxford and other leading universities and research institutions around the world. For more information, please visit here.
Similar Posts:
- What Scientists Really Think About Global Warming
- The EPA Tackles Greenhouse Gas
- Quick Guide to Saving on Gas
- China revises 2008 GDP higher
- Spain’s Debt Maturity Wave Hits Next Month And It’s Already Obvious They Don’t Have Enough Cash
