enter image description here More droughts and heat waves
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.