Historically, carbon dioxide levels have risen after a rise in temperature, not the other way round. Studies show that doubling the amount of carbon dioxide, while holding all other inputs steady, yields a 70% increase in plant growth as well as an increase in agricultural productivity. Moreover, the transportation sector and fossil fuel consumption produce less carbon emissions compared to the likes of what cows and sheep generate through flatulence, belching and manure. The methane thus emitted could be 25 times more potent. Human activity accounts for, some argue, only 2% of global carbon emissions while natural processes like plant decay cause the rest. Though we are emitting much more carbon dioxide than we should, carbon dioxide is not a particularly efficient greenhouse gas. Doubling of carbon dioxide traps less than 2% of the earths outgoing radiation. As for atmospheric carbon dioxide, a giga-tonne added to air has less radiative impact than the previous condition.
The environment works like a commons, where it is pointless if one party confirms to good behaviour when others do not. Prices of negative or positive externalities are high here. Most pollution is a negative externality of our consumption. The incentives and disincentives are weak for reducing consumption. When you look at collective behaviour, these are weaker still. It is even true when our welfare is at stake. If the correlations between knowing and doing were positive, people would never indulge in hazardous behaviour.
Perhaps we require a magic bullet, because people dont respond well if there are no incentives and disincentives. And people dont necessarily change their behaviour even if they stand to benefit the most from the required change. Just like the idea of a zero carbon society is too optimistic, as the half-life of atmospheric carbon dioxide is roughly a hundred years and some of it remains in the atmosphere for thousands of years, similarly solar power is not without problems. It may make global warming worse. Solar cells are black and they are designed to absorb light from the sun. Only 12% gets converted into electricity, and the rest is radiated as heataiding global warming.
Ordinarily, carbon dioxide goes into the troposphere, stays there and then falls down as acid rain. But volcanic eruption sends up sulphur dioxide much more intensely, as the Mount Pinatubo eruption showed in 1991. In such cases, the sulphur dioxide forms an aerosol cloud that circulates rapidly, to envelope most of the globe. After the Mount Pinatubo eruption, the earth cooled off by an average of nearly one degree Fahrenheit, reversing the global warming of 100 years. A National Academy of Science report has floated the idea of intentionally spreading sulphur dioxide in to the atmosphere. This is called the Budyko blanket. When some scientists tried this phenomenon, all they found was that geo-engineering of this sort could stabilise the climate even in the face of a large spike in carbon dioxide. As per Intellectual Ventures estimation, 100,000 tonnes of sulphur dioxide per year can effectively reverse warming in the high Arctic. To most policymakers, this looks like polluting the environment to save it from global warming.
There is a second plan based on extending the smoke stack at a few strategically located carbon dioxide belching power plants. It turns out that the amount of stratospheric sulphur necessary to cool the planet is equal to the amount belched by these plants. But this will have the same cooling effect as the garden hose scheme. John Latham, the British climate scientist who has joined the IV stable recently has brought in another concepta sky full of puffy white clouds. As per Lathams reckoning, a 10-12% increase in the reflectivity of ocean clouds can cool the earth enough to counteract the doubling of current greenhouse gas levels. The strategy is to use the ocean to create more clouds.
Some think that a carbon-induced apocalypse is not logical and we can avert this catastrophe simply by curtailing new carbon emissions. Hence, geo-engineering seems to be an answer. The objection to geo-engineering is that we will be altering the natural state of the earth by scientific intervention. But we have already geo-engineered the earth, havent we
While mankind can go on reducing emissions, it is better to have a geo-engineering backup. Otherwise, at the end of the tunnel, we may find that human beings have not sacrificed as expected. We may find that we were too optimistic while doing too little or that we did too little too late.
This article is hugely influenced by Superfreakonomics. The author is principal secretary & OSD, Government of Andhra Pradesh at New Delhi