EVERYONE knows that the world’s climate is changing and most of us also know that this is because of our own actions. Weird weather conditions are experienced frequently in many parts of the world. Different habitats are changing permanently, making it difficult for its dwellers, both plants and animals (including us humans), to live there.

The climate of our planet has been changing since it was formed. The modern climate era, almost as we know it today that made it possible for human beings to live on Earth, started with the abrupt end of the last Ice Age about 7,000 years ago. The last 100 years have seen Earth’s surface temperature increase by about 0.85°C (1.4F), with 13 of the 14 warmest years were recorded in the 21st Century, and now 2015 is all set to be another recording breaking one as far as soaring temperatures go.

According to The Intergovernmental Panel on Climate Change (IPCC), the leading international body for the assessment of climate change, “Scientific evidence for warming of the climate system is unequivocal.”

That means once a change in climate pattern takes place, there is no way to reverse it. And a change in climate leads to changes in everything on Earth and we will not be able to reverse these changes once they take place. So if the world’s ice caps are melting, sea levels are raising, rainforests are disappearing, droughts and severe hot and cold spells are increasingly taking place, we can’t reverse all these changes.

Though we can’t reverse climate change, there is still much that we can do to stop the conditions from getter worst and our dear Mother Earth turning into a place unliveable for us. If we don’t want to disappear like the dinosaurs, we need to take climate change seriously — each and every one of us — and there is a lot we can do individually and collectively in this regard.

While the heads of states from 147 nations and negotiators from 195 countries are addressing the 21st session of the Conference of the Parties (COP21) in Paris to find ways to reduce global carbon emissions and limiting global warming to 2C (3.6F), let us find out what climate change, global warming and many other related issues are, and what are the causes, effects and solutions of these.

CLIMATE change is the changes taking place on our planet that include global warming, rising sea levels, shrinking mountain glaciers, accelerating ice melt in Greenland, Antarctica and the Arctic, and shifts in flower/plant blooming times.

These are the results of the warming of Earth’s atmosphere, caused mainly by burning of fossil fuels and emission of heat-trapping gases into the atmosphere.

Global warming is the long-term warming of the planet. The terms global warming and climate change are sometimes used interchangeably, but are slightly different things.

Based on current trends, it is likely that Earth will be 4C warmer by the end of this century than it was before the Industrial Revolution, and 3C warmer than it is now. Consequences of climate change

SOME changes to the climate are already apparent while others are likely to take place in the near future. The magnitude of climate change beyond the next few decades depends primarily on the amount of heat-trapping gases emitted globally, and how sensitive the Earth’s climate is to those emissions.

Let’s check out the impacts of climate change.

Sea level

Sea level will rise 1-4 feet by 2100

MELTING land ice and the expansion of seawater as it warms has resulted in global sea level having risen by about 8 inches since reliable record keeping began in 1880. It is estimated to rise another 1 to 4 feet by 2100.

Because the oceans take a very long time to respond to warmer conditions at the Earth’s surface, sea level will continue to rise for many centuries at rates equal to or higher than that of the current century.

HURRICANES will become stronger and more intense

Since the early 1980s, it is seen that the intensity, frequency and duration of North Atlantic hurricanes, and the frequency of the strongest (Category 4 and 5) hurricanes, have all increased.

There will also be an increase in the number, duration and intensity of tropical storms.

Drought

Higher temperatures and up to 30 per cent less rainfall will result in more droughts and heat waves (periods of abnormally hot weather lasting days to weeks), more frequent wildfires and cold waves will become less intense everywhere.

Shrinking ice sheets and melting glaciers

Arctic likely to become ice-free

THE Arctic Ocean is expected to become almost ice free in summer before mid-century. Both the extent and thickness of Greenland and Antarctic ice sheets have decreased in the last several decades.

According to Nasa, data from its “Gravity Recovery and Climate Experiment show Greenland lost 150 to 250 cubic kilometres (36 to 60 cubic miles) of ice per year between 2002 and 2006, while Antarctica lost about 152 cubic kilometres (36 cubic miles) of ice between 2002 and 2005.”

And glaciers are retreating almost everywhere in the world, be it the Alps, Himalayas, Andes, Rockies, Alaska and Africa.

Decreased snow cover

SNOW is melting earlier everywhere and ice on rivers and lakes is breaking up earlier. Satellite images show that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades.

Ocean acidification

OCEANS absorb carbon dioxide and an increase in the amount of carbon dioxide in the atmosphere has increased due to human activity since the Industrial Revolution. The acidity of surface ocean waters has increased by about 30 percent and this acidification of oceans is harmful for marine animals and plants, particularly the coral reefs that are showing a decline due to higher temperatures and acidification of oceans.

Extinction

THE extinction of species will become more likely, with 40 percent of ecosystems affected this century. n

What is greenhouse effect?

TO understand the greenhouse effect we need to understand what a greenhouse is. A greenhouse is a house made of glass where plants are grown. It is particularly useful for growing plants during winter because the temperature stays warm inside despite the cold outside.

During the day sunlight shines in and warms the air inside and the glass roof and walls trap the heat so that it continues to remain pretty warm even during the night.

In the same way, Earth’s atmosphere acts as a greenhouse. A thin layer of gases in the atmosphere, mainly water vapour and much smaller amounts of carbon dioxide, methane and nitrous oxide, act like a glass roof that cloak and protect the planet.

Earth’s surface becomes warms during the day and at night when the surface cools, heat is released back into the air, but the greenhouse gases in the atmosphere trap the heat by absorbing it and re-emitting it in all directions. The energy that radiates back downwards heats both the lower atmosphere and the surface of Earth.

This keeps Earth warm at an average of 15 degrees Celsius (59 degrees Fahrenheit). And without this greenhouse effect, Earth would be about 30C colder, making our planet as hostile to life as the other planets in the Solar System.

However, over the last couple of centuries, we have changed Earth’s atmosphere in a way that the levels of the greenhouse gases have increased, leading to an enhanced greenhouse effect by blocking heat from escaping. This is causing global warming and unprecedented rates of climate change.

The main culprit among these gases is carbon dioxide (CO2) as it stays in the atmosphere for long. Since the industrial revolution began in 1750, CO2 levels have risen by more than 30 percent and its concentration in the atmosphere is now higher than at any time in at least 800,000 years.

We are responsible for this increase of CO2 in the atmosphere through the burning of fossil fuels like coal or oil, and cutting down of trees that could have absorbed some of the excess CO2, and other activities that increase the concentration of greenhouse gases.

The ozone hole is shrinking!

FINALLY there is some good news on the environment and climate front – the ozone hole is shrinking!

Yes, according to a report by Nasa earlier this year, the giant hole is shrinking and “will be effectively extinct by the end of the century”! Nasa reports that evidence now suggests that the hole which is currently 12 million square miles, will be fully recovered by the end of the 21st century.

The ozone hole is basically a man-made hole in the ozone layer above the South Pole during the Southern Hemisphere’s spring. The ozone layer in Earth’s atmosphere shields us from harmful ultraviolet (UV) rays that come from the sun. The hole was first discovered 30 years ago by UK scientists studying Antarctica. The threat was major — the hole increased levels of cancer-causing solar radiation and could cause large-scale health risk.

The use of gases like chlorofluorocarbons (CFCs) in spray cans and refrigerants, has led to the breakdown of ozone molecules in the upper atmosphere, leading to a hole in it.

Scientists believe the ozone hole has affected the climate in the Southern Hemisphere, causing faster winds near the Pole and this impact goes as far as the Equator, affecting tropical circulation and rainfall at lower latitudes. It can be said that the ozone hole is not causing global warming, but it is nevertheless affecting atmospheric circulation.

But since the Montreal Protocol agreement in 1987, the emissions of CFCs have been in decline, as ozone-friendly alternative chemicals have come into common usage.

Ways to reduce greenhouse gases

BURNING fossil fuels such as natural gas, coal, oil and gasoline raises the level of carbon dioxide in the atmosphere, leading to the greenhouse effect and global warming. We can reduce the demand for fossil fuels by becoming more energy-efficient

Reduce, reuse, recycle

BUY products with minimal packaging and recycle your household waste.

Use less heat and air conditioning

INSULATE the roof and walls. Build eco-friendly homes to reduce the amount of energy required to heat or cool the home.

Use florescent light bulbs

REPLACE regular light bulbs with compact florescent light (CFL) bulbs. They require less energy and last longer.

Drive less, drive smart

WE need to reduce the number of cars on the roads as every gallon of fossil fuel saved keeps 20 pounds of carbon dioxide out of the atmosphere and save you money too.

Use less water

WHEN brushing your teeth, washing the dishes and clothes and doing other water-related chores, turn off the water until you actually need it for rinsing.

Keep water geysers turned to low heat until you need to take a bath. Use low-flow showerheads to save hot water and water in general.

Switch off!

TURN on only those lights in the house that you need, and turn it off when you leave the room. Keep other electrical appliances, such as TV, AC and computers, turned off when not in use.

Plant trees

AS trees absorb carbon dioxide and give off oxygen, we can turn to this natural way of reducing carbon dioxide in the air. A single tree will absorb approximately one tonne of carbon dioxide during its lifetime. — A.A.