Written by Naina Mahajan, a grade 6 student.

Global warming has been a pretty hot topic for a long time now. Literally. It is caused by the “greenhouse effect”.

Global warming comes under the broader topic of climate change, which not only includes global warming but also the “side effects” of warming, which include glaciers melting, sea levels rising as a result, oceans warming, storms, heatwaves, and more frequent and intense droughts.

All of these have a terrible effect on animals, harming them and destroying their habitats, and wreaking havoc on human life, their livelihoods, and communities.

What is the “greenhouse effect”?

When sunlight falls on the Earth, some of it is reflected off the surface of the Earth and is absorbed by greenhouse gases like carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) present in the atmosphere. This sunlight absorbed by the gases is then reflected again, and thus warms the Earth.

But the greenhouse effect doesn’t only occur at the planetary scale. It got its name by how glass greenhouses where fruits, vegetables, flowers and any other type of plant are grown that require special conditions of temperature. In these greenhouses as well, the greenhouse effect can be observed.

You may have noticed that when your car is parked out in the Sun on a hot day, if the car doors are closed and the windows are all up when you get inside and sit down, your seat is very hot. This is also an example of the greenhouse effect. Glass is best for the greenhouse effect because it traps heat within the structure, as in the case of cars or greenhouses.

Earlier, this effect wasn’t that bad, in fact, it was essential for the survival of life as we know it. Without this effect, the Earth would be too cold for life to survive on it. But in the 1980s, the Earth started warming up a little too much.

The beginning of the end

In the 1970s, and ever since then, the emission of different greenhouse gases soared. Carbon dioxide emissions have increased by about 90% since 1970. This heated up the Earth more than required, causing an issue dubbed “global warming”. Stephen Hawking, the great theoretical physicist, predicted that Earth would turn into a giant ball of fire by 2600 if we don’t do something about global warming.

Global warming has affected millions of people over many years now, but it has affected animals the most. Sea animals and polar bears especially.

How global warming has affected polar bears

Polar bears live in the Arctic region, that is, in the North Pole. While they are supremely talented swimmers, they prefer to live on the ice that covers the Arctic seas throughout most of the year.

With the rising temperatures caused by global warming, the Arctic ice is melting at a steep rate. Scientists who conducted a study predict that polar bears could go extinct by the end of the century unless we tackle climate change in a big way.

During the winter, most of the ice freezes over again, and scientists expect that this will continue for the foreseeable future, even though the climate continues to warm. In the summer, some of the ice melts, the winds and currents carry it over the sea and far away. Some of the ice is carried to the North-Atlantic, but most of it lands upon the Arctic’s coasts that are farthest north, along Greenland and the Canadian islands.

The results?

A rich and biodiverse marine ecosystem. On the ice, algae bloom, and this feeds tiny animals, which feed fish, which feed seals, which feed polar bears. The chain ends with polar bears at the very top. The topography (physical features of the land) becomes irregular and this helps create ice caves for polar bears to take shelter during winter and dens for seals.

But what also happens during the summer, when some ice melts, is that polar bears swim most of the time. However, they can’t swim all the time and need to rest on land too. With the rising temperatures, the ice is melting at a faster rate and there isn’t enough frozen ice, for the polar bears to live on, during summer. With the climate becoming warmer and warmer, the area the summer sea-ice covers have been shrinking rapidly, and currently spans less than half of what is covered in the early 1980s.

A recent study conducted has researched an area covering 1 million square kilometers (about the size of Egypt) in the region north of Greenland and along the coasts of the Canadian Archipelago, which is the huge group of islands crowning North America. These are the places where the sea ice has been thickest all year traditionally and is thus likely to be the most resilient as well.

The researchers took on two viewpoints to this problem:

a. Optimistic (the glass is half full) where the carbon emissions are brought under control, and

b. Pessimistic (the glass is half empty) where carbon emissions continue as they are right now.

Predictions state that by 2050, the summer ice in this region will thin dramatically. This means that the ice is melting faster than it’s re-freezing. In the optimistic case, some of the summer ice could be there indefinitely and even with low emissions, ice from the central Arctic itself would wane by mid-century and will not live through the year. Locally formed summer ice that was not carried from the Arctic might persist in what scientists have dubbed ‘the Last Ice Area’, but it would only be around a metre in thickness. In the pessimistic case, the summer ice disappears by the end of the century.

The study foresees that under the low emissions scenario, at least a few seals, polar bears, and other creatures might survive. This is proven because these species currently live under similar conditions along with western Alaska and parts of the Hudson Bay. However, by 2100, even the locally formed ice would disappear, the study has discovered. With no summer ice, there would no longer be any ice-dependent ecosystems.

What we can do to stop the extinction of polar bears and other Arctic animals, is trying to save our environment by using more biodegradable, more eco-friendly modes of transportation. Not to mention, just in time for Diwali, not burst as many crackers.

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