That we are heading towards a warmer (scorching hot?) climate is established beyond doubt. The differences lie only in the estimate of the rate at which we are hurtling towards it. It is also widely believed that increase in the greenhouse gases, in the atmosphere, is responsible for the increase in the temperature. This article starts with a primer on man made global warming and ends with some technology solutions, that may help us avoid the most devastating consequences, while we make our peace with Earth.
Most of you are aware of global warming, but when do you think it all started? Let me make the question unambiguous, when do you think “man made” global warming started? Approximately 200 years ago, the time since the huge industrial machines started spewing carbon dioxide and methane in the air? Correct? No, wrong! The correct answer, probably, is 8000 years ago.
Initially, global warming was beneficial. It helped extend the interglacial period (The warm period between two glacial ages) in which we live. If it were not for the man made global warming, Earth would have plunged into an ice age, approx. 5000 year back. However, man made global warming is one good thing that has been abused, knowingly and unknowingly; to an extent that now it threatens our collective existence. When I say collective existence, I mean entire life form on Earth, the whole jing bang and not just humans.
Earth began its existence approximately 4.4 to 4.5 billion years ago. For initial 2 to 2.5 billion years, it is mostly believed, Earth was hot and hellish. Around 2.7 to 2.3 billion years ago, it started to cool and froze. That was the first of the 4 ice ages that it has seen so far. The 2nd Ice age was approximately 850 to 630 million years ago. It was supposed to be so severe that it produced a snowball earth. The entire globe was covered with snow. A minor ice age occurred 350 to 260 million years ago. The present ice age started approx. 40 million years ago with growth of ice sheet over
The magic stick that stalled the ice age is called agriculture - particularly wet agriculture, such as practiced in flooded rice paddies in
Agricultural practices like this and the farts and belches from animals are a major source of Methane in the atmosphere.
So what’s the connection between methane and global warming? Methane is one of the greenhouse gases. Greenhouse gases prevent heat from escaping the Earth and hence act as a glass shield, which lets the heat come inside but does not let it escape. The toasty inside of a car, sitting in sun, is all too familiar. The greenhouse gases work on the same principal, they make an invisible envelop around the Earth and prevent the heat from escaping the Earth.
There are bunch of other gases which are categorized as greenhouse gases. The most abundant greenhouse gas is carbon dioxide, then is methane, nitrogen oxide (laughing gas) and bunch of others. All of these greenhouse gases, combined together, do not even make one twentieth of one percent of the total atmospheric gases. But, it is this one twentieth of one percent that makes it all so interesting.
Initially, the additional Methane produced by human activity, increased the global temperature just enough to thwart the onset of the ice age. However, the humans did not know this and continued in the pursuit of “progress” which was heavily dependent on extracting energy from fossil fuel. So what’s wrong with that? Nothing, till you realize that all fossil fuel burning, whether, it is coal, or oil, or gas, releases carbon dioxide, which is a greenhouse gas and hence leads to increase in temperature!! Fair enough, what’s wrong with increase in temperature? Isn’t it something that anyway happens as part of the natural cycle? Aha, did you say natural cycle? That is exactly the point, when the change in climate is part of the natural cycle, it happens over a period of time that allows various species to adapt to the changing climate. However, when natural cycle is tinkered, it has consequences that are sudden and catastrophic, giving little chance to Earth to offer soft landing to its inhabitants.
We are at a stage, where irreversible changes have been done to the atmosphere. The point to note here is the fact that the changes done to the atmosphere haven’t yet shown completely in the oceans. Given that the oceans lag behind the atmosphere by approximately 30 years, our oceans are still living in 1970s. When the oceans catch up with the warming trend of our atmosphere, it will result in increasing stratification of the oceans. Stratification means the top warm layer of water gets lighter and floats on the lower cooler layers without ever mixing with it. This leads to a peculiar problem, the top layer that gets all the sunlight, does not get enough nutrients and hence can’t support any plant life. The lower layer that has all the requisite nutrients does not get any sunlight hence can’t support the plant life. The net effect is the breakdown of the food chain since the microscopic plants - planktons - that are at the base of the food chain, dwindle in numbers. Dwindling planktons result in positive feedback for global warming as there are less plants to extract carbon dioxide from the atmosphere resulting in even warmer climate.
Having gone thru’ a primer of global warming and its perils, question pops up - can something still be done to avoid the disaster or is it too late? Well, the answer may be “We don’t know if we are already late or not, but just in case there is still some time, here’s a list of actions that can help”. Actions can be divided into two categories –
a) Reduce the input of heat from the source i.e. sun
b) Take out the greenhouse gases from the atmosphere
These two set of actions can only help us buy some time, so that we change our extravagant ways and make our peace with Earth.
Some proposals that have the potential to reduce heat from the source –
- Space sunshade, placed between the Sun and the Earth, at Lagrange point. It is the point where the gravitational pull between Earth and the Sun is equal. This sunshade can help reflect or disperse some percentage of incoming sunlight, thus cooling the Earth.
- Artificial production of stratus clouds over ocean surface, by converting sea water into an aerosol of tiny particles that can serve to increase the density of the clouds. These clouds are proven to reflect sunlight back in space and hence can help cool the Earth.
- Injecting sulphur dioxide in the stratosphere(This is 2nd layer of atmosphere. Just above the troposphere) where it is oxidized to form an aerosol of sulphuric acid droplets. These droplets remain suspended for years and help reflect the sunlight back thus reducing the greenhouse effect.
Some proposals to take out greenhouse gases from the atmosphere –
- Collect the carbon dioxide directly from the smoke stacks and sequester it safely. One sequestering option is to pump the recovered carbon dioxide in underground storage; however this is prone to leakages etc. One novel method suggested is to make the recovered carbon dioxide react with chalk suspended in water. This would produce a solution of calcium bicarbonate which is easy to dispose.
- Remove carbon dioxide directly from air with artificial photosynthesis and make it react with powder made from alkaline igneous rocks called serpentine.
- Fertilize the oceans, with iron, to increase the plankton(The microscopic plants that are the source for most oxygen in the atmosphere and also are at the bottom of the oceanic food chain) numbers and there by increase the natural recycling of carbon dioxide and also boost the ocean life.
All the above solutions, proposed by eminent scientists, are the solutions that are good enough only to buy some time, while a long term fix is found to this perplexing problem. As the noted climatologist James Lovelock says, the key to finding a long term solution is that we must approach it from “sustainable retreat” perspective vs “sustainable development” perspective.
No comments:
Post a Comment