Can geoengineering schemes fix climate change?
— Photo: AFP
Volcano factor: Volcanoes have cooled the planet whenever they have erupted.
Whatever remedial measure that we undertake now will not affect the climate for the next 20-30 years but will influence the climate only after 2040. The most promising solutions that Prof J Srinivasan, Chairperson of the Divecha Centre for Climate Change, Centre for Atmospheric Sciences, IISc, Bangalore, and Prof Dr. Govindswamy Bala, Associate Professor, Divecha Centre for Climate Change, IISc, Bangalore, suggest to fix our troubled climate are the renewable energy and geoengineering solutions.
The government already aims to make India a global leader in solar energy and aims at producing 200,000 MW by 2050. Renewable energy sources in generating electricity have not made a big difference in the past as the cost of installation was five times that of coal. Solar-based power plants require more land compared to oil or coal based power plants. Gujarat and Rajasthan could support them. Germany and Japan are making a huge transition in this direction. Germany has convinced its government to phase out coal-based power plants. Germany and Saudi Arabia have plans to generate hydrogen using solar photovoltaic cells in the deserts and ship it to Germany. European nations have taken the climate change issue more seriously than USA.
Prof. Bala is working on geoengineering experiments along with scientists from Stanford University. The researchers studied the effects of increasing greenhouse gases and sunlight on our planet’s water cycle using a global climate model. Their findings could have implications for the so-called “Solar Radiation Management (SRM)” geoengineering schemes.
These schemes counter the global warming effects of anthropogenic greenhouse gases such as CO{-2} and methane by reducing the amount of solar radiation that is absorbed by the Earth. Placing reflecting mirrors in space, injecting aerosols into the stratosphere, enhancing the albedo of marine cloud by seeding them with cloud condensation nuclei, and painting the roof white are some examples of the SRM geoengineering schemes. To counter climate change from a doubling of CO{-2}, Prof. Bala says, approximately 2 per cent of incoming solar energy needs to be reflected back.
The gravitational forces balance each other at the L1 (La grande) point between the Earth and Sun. If mirrors are installed at this point, it is easier and cost effective to maintain. The next possibility is spraying sulphate aerosols into the earth’s atmosphere, as they are good reflectors. Prof Bala says that the earth’s history shows that volcanoes have cooled the planet whenever they have erupted. What if we have artificial volcanoes and inject aerosols to cool down the planet? These aerosols settle down after a couple of years and have to be replenished.
How practical are the costs of these schemes? Prof Bala says that each ton of Carbon dioxide in the atmosphere leads to climate change. However the so-called air-capture-of CO{-2} that removes atmospheric CO{-2} through chemical reactions costs about $200-500 per ton of carbon. In comparison, the former geo-engineering schemes are economically viable.
PAPIYA BHATTACHARYA
Printer friendly
page
Send this article to Friends by
E-Mail
Sci Tech
