What is climate change?

Climate Change is a periodic modification of Earth’s climate brought about due to the changes in the atmosphere as well as the interactions between the atmosphere and various other geological, chemical, biological and geographical factors within the Earth’s system. It is a global threat to security in the 21st century. It is causing weather events like more frequent and intense hurricanes, floods, cyclones, flooding etc. Due to the rising temperature caused by climate change, the ice in the polar regions is melting at an accelerated rate, causing sea levels to rise. This is damaging the coastlines due to the increased flooding and erosion. The cause of the current rapid climate change is due to human activities and threatening the very survival of humankind.


Cause of Climate Change

1.Solar variability

The brightness (luminosity) of the sun has been increasing since its formation. This phenomenon is important to Earth’s climate, because the energy received from the sun is used to drive atmospheric circulation and constitutes the input for Earth’s heat budget.

While the sun goes through natural cycles, there is a variation in the amount of energy that it emits to the earth.

2.Greenhouse Gases

These are gas molecules that have the property of absorbing infrared radiation emitted from Earth’s surface and reradiating it back to Earth’s surface. Greenhouse gases play a vital role in the earth’s climate change. As the planet gets hit with the sun’s rays, some of the energy is absorbed, and the rest of that energy and heat gets reflected into space. Carbon dioxide, methane and water vapour are the most important greenhouse gases.

Greenhouse Gases

Some of these greenhouse gases, such as water vapour, are naturally occurring, but others, such as CFCs, are synthetic. CO2 is released into the atmosphere from both natural and human-made causes and is one of the leading contributors to climate change. CO2 has been increasing at an alarming rate and has the potential to stay in the earth’s atmosphere for thousands of years unless it gets absorbed by the ocean, land, trees, and other sources.

3.Volcanic Activity

Volcanic eruptions can release large quantities of sulphur dioxide and other aerosols into the atmosphere reducing atmospheric transparency and thus the amount of solar radiation reaching Earth’s surface and troposphere.

Volcanic Activity

4. Agriculture

Agriculture also impacts climate change. Deforestation in places like the Amazon and other forests around the world, agriculture is responsible for a significant portion of the world’s greenhouse gas emissions. However, agriculture is also an area that is making tremendous strides to become more sustainable. As productivity increases, less carbon is being emitted to produce more food. Agriculture also has the potential to act as a carbon sink, and could eventually absorb nearly the same amount of CO2 it emits.

5. Human Activity

The most significant contributor to climate change is the burning of fossil fuels for electricity, heat, and transportation. Of these factors, transportation in the form of cars, trucks, ships, trains, and planes emits the largest percentage of CO2–speeding up global warming and remaining a significant cause of climate change.

Evidence for Climate Change

1.Global Temperature Rise: The planet’s average surface temperature has risen about 0.9 degrees Celsius since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere. Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010.

2.Increased sea surface temperature: The oceans have absorbed much of this increased heat, showing warming of more than 0.4 degrees Fahrenheit since 1969.

3.Melting Ice Sheets: The Greenland and Antarctic ice sheets have decreased in mass. Data show Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same time period. The rate of Antarctica ice mass loss has tripled in the last decade.

Evidence for Climate Change

4.Glacial Retreat: Glaciers are retreating almost everywhere around the world including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.

5.Decreased Snow Cover: Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier.

6.Sea Level Rise: Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century and is accelerating slightly every year.

7.Declining Arctic Sea Ice: Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.

8.Extreme Events: The number of record high-temperature events has been increasing, while the number of record low-temperature events has been decreasing, since 1950.

9.Ocean Acidification: Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 per cent. This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.

Potential impact of climate change

1.Extreme Heat: Unusual and extraordinary spells of hot weather are expected to occur far more frequently and cover much larger areas.

2.Changing Rainfall Patterns: A decline in monsoon rainfall since the 1950s has already been observed. At 4°C warming, an extremely wet monsoon in the equatorial region that currently has a chance of occurring only once in 100 years is projected to occur every 10 years by the end of the century. Dry years are expected to be drier and wet years wetter.

3.Droughts: have major consequences it affect all around the world and led to a huge fall in crop production. Droughts are expected to be more frequent in some areas. Crop yields are expected to fall significantly because of extreme heat by the 2040s.

Potential impact of climate change

4.Groundwater: Groundwater resources are overexploited. Falling water tables can be expected to reduce further on account of increasing demand for water from a growing population, more affluent lifestyles, as well as from the services sector and industry.

5.Glacier Melt: At 2.5°C warming, melting glaciers and the loss of snow cover over the poles are expected to threaten the stability and reliability of glacier-fed rivers. Alterations in the flows of major rivers could significantly impact irrigation, affecting the amount of food that can be produced in their basins as well as the livelihoods of millions of people.

Sea level rise: Sea-level rise and storm surges would lead to saltwater intrusion in the coastal areas, impacting agriculture, degrading groundwater quality, contaminating drinking water, and possibly causing a rise in diarrhoea cases and cholera outbreaks, as the cholera bacterium survives longer in saline water.

Climate change could push more than 100 million people into extreme poverty by 2030 by disrupting agriculture and fuelling the spread of malaria and other diseases, the World Bank said in a report. From shifting weather patterns that threaten food production, to rising sea levels that increase the risk of catastrophic flooding, the impacts of climate change are global in scope and unprecedented in scale. Adapting to these impacts in the future will be more difficult and costly. We must act now to limit future risks to the planet we share and the impacts we going to face.