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Scientists, journalists and activists have been warning the world about climate change for the last couple of decades, and in increasingly dire words. Yet, climate action has hardly moved forward. What movement we see is too little, too late.
Is it that we do not know enough to care? What is climate change really? What are greenhouse gases and what exactly do they do? Are there policy-level actions addressing this issue? What role is technology playing? How will climate change affect us personally? What can we do to help?
Backstage Climate: The Science and Politics Behind Climate Change is a highly readable primer on a pressing issue—the one book you need to gain a global sense of a subject that will soon come to dominate every conversation. Through short pieces and engaging illustrations, the book attempts to demystify climate change and explain what the fuss is all about and why it matters very much.
Here's an excerpt on
Come October and the dining-table conversations in Delhi switch to air pollution. The sky turns grey. People start coughing and choking. Air purifier sales shoot up, and the discerning start wearing face masks. Hospitals do brisk business and our politicians scurry, looking for places to hide.
Delhi is not unique. A similar problem exists in many other cities in the developing world. Neither is the problem new. Most big cities even in the developed world—London, Los Angeles, Tokyo— have all gone through similar air pollution issues in the past and fortunately stand clean now. Notwithstanding, the issue this time seems more pronounced and complicated. There are two ripples in the pond, air pollution and climate change, originating from a single act: human activity. These are two sides of the same coin.
Air pollution is generally local and often temporary. It can affect a city or state, and if adequate measures are taken, it can be overcome in a few years. Climate change, on the other hand, is global and is a more lasting issue. Air pollution manifests itself through our sensory instincts like colour, odour or particulate matter that we see and feel in the air we breathe. Climate change manifests itself through a change in temperature, extreme weather and their corollary effects. Air pollution causes immediate health problems. Climate change can cause both health and infrastructural damage, usually on a longer time scale.
The causes for both are the same—fossil fuels, industry and land use changes.
Fossil fuels used in power plants and transportation emit greenhouse gases like carbon dioxide, nitric oxides, sulphur dioxide, volatile organic compounds and also some particulate matter like elemental carbon, which we call soot. Industry emits carbon dioxide and other complex gaseous and solid particulate matter. Land use changes contribute both carbon dioxide and dust through denudation and deforestation. All these cause both pollution and climate change.
Nitric oxides and volatile organic compounds, through complex atmospheric reactions, are responsible for the creation of ground ozone, which creates the visible smog that we see hanging around. This is further compounded by the elemental carbon particles and sand dust that remain suspended in the air and reduce visibility.
Then there is stubble—the remains of rice paddy plants that are left in the ground after harvesting. Come October and stubble burning starts in the surrounding agricultural belts of Delhi, contributing to Delhi’s pollution woes.
October is also the time when there is a lull in air movement and the ground temperature starts falling. This causes temperature inversion—cold air laden with polluting particles gets entrapped by an envelope of warm air above it, thus restricting its vertical movement. That’s how we see haze all around for days.
The particulate pollutants are classified by their size and the most lethal ones are PM 2.5 which, being miniscule, find it easy to get into our lungs and bloodstream.
Pollutants have a love–hate relation with climate. Most of them like carbon dioxide, nitric oxides and others are greenhouse gases and cause global warming by entrapping heat. Likewise, elemental carbon, which is black in colour, settles on white surfaces and causes them to darken. As a result, they cause these surfaces to absorb heat instead of reflecting heat back into space. On the other hand, some of the particulate matter and gases like sulphur dioxide form aerosols in the air and reflect heat from the sun instead of absorbing it, thus creating a cooling effect.
Air pollution remains a temporary and a local issue as the particulate matter gets blown away when winds resume, rain falls and some of the suspended particles settle down. Greenhouse gases, on the other hand, remain in the air for very long durations and continue to cause global warming, even if they are swept by the wind or wet by the rain.
The effects of climate change can exacerbate pollution. Forest fires caused by the drying up of forests can add a significant amount of particulate matter to the air. Look what has been happening in California, Canada and many other parts of the world, with forest fires raging across the surface of the land. Similarly, floods caused by climate change, not only bring destruction but also catalyse decomposition of organic matter, giving rise to methane emissions and bacteria, which then remain suspended in the air.
Climate change can also affect local pollution in other ways. It is said that the problem of pollution in Delhi in October and November is a recent occurrence. One of the effects of climate change has been a shift in the timing of monsoons, which in turn have delayed the paddy growing season, thus pushing its harvest to October and November. This leaves very little time for the farmers to clear the fields and sow their next crop and hence, they end up burning the stubble to clear the fields. This burning of stubble now synchronises with the stillness of air and the fall in temperature around that time. All this, coupled with the fossil fuel exhaust coming from twelve and a half million vehicles in Delhi, and the perennial dust from construction activities, causes the pollution levels to shoot up exponentially during these months.
While the air pollution subsides somewhat in the months that follow, the greenhouse gases remain.
The good news is that we can kill two birds with one stone. Our actions to mitigate greenhouse gas emissions to rein in climate change can also help mitigate pollution and vice versa. Mending fossil fuel usage, encouraging industry decarbonisation and land use preservation remain our solutions for both.
Excerpted with permission from Backstage Climate: The Science and Politics Behind Climate Change by Rajan Mehta, published by Westland Books.