Jan 24, 2019
Weather vs Climate: Unwittingly, I started writing this article at a time when 85% of the USA was below the freezing temperatures and parts of the Punjab were covered under a foot of hail, very unusual, end-of-the-January weathers. This may seem to make my argument of Global Warming rather weak. However, before we jump to that conclusion, let’s look at the terms weather and climate. Weather refers to the atmospheric conditions like rain, wind, sunshine, visibility etc., at any given time. For example, we can say that we have rainy weather today or that Patiala had nice sunny weather on January 25, 1850. Weather can change suddenly – like sudden rain or a sudden hail storm. With climate, however, we talk about atmospheric conditions averaged over a long period, usually thirty years. Even though some summer days in Rajasthan may be cold and rainy, but climatically summers in Rajasthan would be called hot and dry. The current hail storm in the Punjab and the unusually freezing temperatures in the US represent variations in the weather. We may not see another hail storm this intense, in the Punjab for decades.
Now back to the topic at hand. Why do we want to talk about Global Warming? The answer is simple, because, number one, Global warming is changing the climate of our earth in a significant and a negative way, number two, we have no right to leave behind an irredeemable climate for our children and number three, today, we have the power and the means to control this change. To understand Global Warming, we must first talk about the greenhouse effect.
Greenhouse Effect: The sun shines on the earth 24 hours a day, heating it up, constantly. However, the heat from the earth escapes into space. If all the heat from the sun escaped into space, Earth will become like Mars, a frozen surface with no life. Fortunately, our atmosphere contains many elements like water vapor, carbon dioxide, methane, nitrous oxide, ozone that absorb heat and slowly re-radiate it, keeping us warm. This effect of gases is called the Greenhouse Effect. The average temperature of our earth is 15 degree Celsius. However, if it were not for our atmosphere, the temperature of the earth would be 18 degrees below zero.
Global Warming: Lately our atmosphere is getting thicker and as a result, the earth is getting warmer due to higher levels of re-radiation. That is called Global Warming. Although Global Warming is a more complicated process, the main reason for the atmosphere getting thicker is the higher levels of carbon dioxide emissions. Where does carbon dioxide come from? The carbon dioxide is the waste product of all the coal and the gasoline we burn. All those cars, trucks, locomotives and fifteen gallons second gasoline-burning jets, throw carbon dioxide into the atmosphere. Common folks make their due contribution by burning things like wood, rice straw or other crops. All those fireworks we enjoy during Diwali and other celebrations are worthy culprits. Chlorofluorocarbons or CFCs are other manmade chemicals released into the atmosphere that not only increase the greenhouse effect, but they also destroy the friendly ozone in the atmosphere. Our criminal act does not end just here, we also kill the good guys – the plants. The plants consume carbon dioxide and convert it into hydrocarbons and oxygen. Heavy deforestation is resulting in the loss of these beautiful allies of the climate. Just to have an idea, the concentration of carbon dioxide around the year 1750 was 280 ppm and today it is 406 ppm – a 45% increase and all the credit goes to us, human beings.
Climate change: The United Nations’ Intergovernmental Panel on Climate Change (IPCC) A United Nations body for assessing the science related to climate change, predicts that over the next century, the average earth temperatures will increase between 1 to 3 degrees Celsius, the rise being as high as 5.6o C, for certain regions of the world. Is this significant? Last October a United Nations report compared the changes that will happen if the temperatures rose by 1.5 degrees vs 2 degrees. The following table shows that comparison:
|**||Temp rises 1.5 degrees||Temperature rises 2 degrees|
|Sea Ice in the Summer||Seas will have Ice in Summer||Seas will be Ice Free|
|People impacted by Severe heat wave||14% of the world population||37% of World Population|
|Water Scarcity Impact||350 million people impacted||411 million people impacted|
|Insects||6% will disappear||18% will disappear|
|Plants||8% will disappear||16% will disappear|
|Vertebrates||4% will disappear||8% will disappear|
|Coral Reef||Frequent mortalities||All coral Reef will die|
|People impacted by Sea level rise||31 – 69 million||32 – 80 million|
**Ref: NY Times, Oct 7, 2018
As compared with sixty years ago, we are already seeing rising seas and increased coastal flooding, longer and more damaging wildfire seasons, more destructive cyclones and more frequent and intense heat waves. By the end of this century, sea levels are expected to rise one to four feet. Glacier is already shrinking, and the Arctic will likely become ice-free. Already shifting Plants and Animal ranges will shift more, the plant growing, and flowering seasons will shift, and crop yields will decrease.
Can we do something about it? Yes, we can stop this change by reducing emissions of greenhouse gases and stopping deforestation. However, it is easier said than done. In 2015, all countries except Syria and Nicaragua signed an agreement, known as the Paris agreement, to reduce emissions of greenhouse gases. In comparison with 2005 emissions, China pledged to reduce emissions by 60-65% by 2030, the US by 26-28% by 2025, EU by 40% (as compared with 1990) by 2030 and India by 33-35% by the year 2030. Unfortunately, under Trump, the United States pulled out of the Paris Agreement. Luckily a few US states including the largest state of California are still committed to this agreement. Let us hope that the USA elects a saner President soon and meets in entirety, her obligation to the Paris agreement.