Updated: May 7, 2020
I’m sure most of us are aware of the climate emergency prevalent in today’s world. The annual average temperature across the world has been increasing at an alarming rate, especially after the industrial revolution in the 18th and 19th century. The primary reason for this climate emergency is the greenhouse effect. So what really is the greenhouse effect?
The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without this atmosphere. So in layman's terms, it is something like the greenhouses we see often in nurseries and gardens to keep tropical plants warm even when the outside temperature is unfavourable. These greenhouses have a roof and walls made of tinted glass which allows the heat from the sun to enter by the process of radiation but does not allow the heat to escape, which consequently raises the temperature of the greenhouse, making it suitable for the growth of these tropical plants. Similarly, certain gases in the atmosphere such as carbon dioxide, methane, nitrous oxide, and fluorinated gases trap these radiations from the sun, which increases the temperature of the earth and makes it habitable for the organisms that call it home. During day time, the sun's heat reaches the earth's surface and heats it. During the night, however, the surface of the earth cools down considerably, and releases the heat into the atmosphere but is trapped by these greenhouse gases. This is crucial as it keeps the earth's average temperature at around 14 degrees celsius and prevents our planet from freezing over.
So now that you know the greenhouse gases are crucial in maintaining the earth’s climate, it probably seems the greenhouse effect is more of a boon than a bane. This is how the problem arises. Human activities such as the unchecked and indiscriminate burning of fossil fuels like coal and petroleum and practicing unsustainable food production methods like factory farming for economic development are releasing inflated amounts of greenhouse gases into the atmosphere, and we know that more carbon dioxide equals more heat trapped by the atmosphere which causes the earth to warm up. This leads to what we call "Global Warming".
Most of us have heard of global warming and its consequences through newspapers, documentaries and science textbooks. This unprecedented rise in earth's temperature can be attributed to the rise in the amount of greenhouse gases in the atmosphere due to urbanisation and industrialisation. According to the United States Environmental Protection Agency (EPA) worldwide net emissions of greenhouse gases from human activities increased by 35 percent from 1990 to 2010. Emissions of carbon dioxide, the primary greenhouse gas increased by a staggering 42 percent during this period. Measurements of carbon dioxide from the Mauna Loa observatory in Mauna Loa, Hawaii show that concentrations have increased from about 313 parts per million (ppm) in 1960, crossing the 400 ppm milestone on May 9, 2013. Now that we have established that the increase in the concentration of these greenhouse gases is the principal cause for global warming, let me explain what this has already done to our beautiful planet and the potential ramifications the continued emission of these greenhouse gases could have in the near future if we leave it unchecked.
The immediate and main effect of global warming is the increase in temperatures globally. The average global temperature has increased by close to 1-degree celsius over the past century according to the National Oceanic and Atmospheric Administration (NOAA). Since record-keeping began in 1895, 2016 was the hottest year on record worldwide. What's interesting is that the hottest year on record before 2016 was 2015. Before 2015, the hottest year on record was... 2014. I'm definitely beginning to see a pattern here that I don't like. The second effect is the increasingly frequent appearance of extreme weather events. Many places on earth have not only experienced their hottest summers on record but also are experiencing colder than normal winters. Other extreme weather events may include the increased frequency and intensity of hurricanes in particular areas such as the Philippines, the increased frequency of floods and the increased frequency of lightning among other events. Another highly publicised effect of climate change is the melting of earth’s ice, especially glaciers and the polar ice caps. According to a 2016 research published in the journal, ‘Climate Change’, North America, Europe and Asia have all seen a trend towards lower snow cover between 1960 and 2015.
It is widely acknowledged that as the ice caps melt, sea levels rise, which makes the increase in sea levels dependent and proportional to the previous effect. In 2014, the World Meteorological Organisation reported an increase of 3 millimetres. It might not sound like a lot, but to put things into perspective the global sea levels rose only by 1.6 millimetres in the entire 20th century. If the trend continues then by 2100 the sea level will be 0.7 metres higher than New York and 4 metres higher than Chennai. As levels of carbon dioxide increase, some of it is absorbed by the oceans and its water turns into carbonic acid, similar to a can of soda. For reference, a can of coke has a Ph value of 2.52. Now imagine fish living in it!
Global warming has profound and far-reaching consequences on the earth's ecosystems. Many species of plants and animals are moving their range towards more suitable environments, but species that won't be able to adapt fast enough to the new climate regime will undoubtedly go extinct. Thus, it is evident that the continued anthropogenic (chiefly of environmental pollution and pollutants) emissions of these greenhouse gases has and will most likely cause many more ecological issues for our planet. If you managed to scroll down and read the 1000 or so words that I wrote, you know that it's imperative that the whole human population takes responsibility and works to reduce emissions of greenhouse gases. It is also important for us to work at an individual and community level to help reduce emissions and save our planet.
Edited by Arjun Krishnan.