Here’s how greenhouse gases actually warm the planet

Bhubaneswar: Greenhouse gas (GHG) emissions are atmospheric gases responsible for causing global warming and climatic change. While most GHGs are naturally occurring, human activities have also been leading to a problematic increase in the amount of GHG emitted and their concentration in the atmosphere.

This increased concentration, in turn, can lead to adverse effects on climate. Effects include increases in the frequency and intensity of extreme weather events – including flooding, droughts, wildfires and hurricanes – that affect millions of people and cause trillions in economic losses.

What are the major greenhouse gases?

Carbon dioxide (CO2), methane and nitrous oxide are the major GHGs. CO2 stays in the atmosphere for up to 1,000 years, methane for around a decade and nitrous oxide for approximately 120 years. Measured over a 20-year period, methane is 80 times more potent than CO2 in causing global warming, while nitrous oxide is 280 times more potent.

Coal, oil and natural gas continue to power many parts of the world. Carbon is the main element in these fuels, and when they’re burned to generate electricity, power transportation or provide heat, they produce CO₂, a colourless, odourless gas.

Oil and gas extraction, coal mining and waste landfills account for 55 per cent of human-caused methane emissions. Approximately 32 per cent of human-caused methane emissions are attributable to cows, sheep and other ruminants that ferment food in their stomachs. Manure decomposition is another agricultural source of the gas, as is rice cultivation. Human-caused nitrous oxide emissions largely arise from agriculture practices. Bacteria in soil and water naturally convert nitrogen into nitrous oxide, but fertilizer use and run-off add to this process by putting more nitrogen into the environment.

What is the greenhouse effect?

The Earth’s surface absorbs about 48 per cent of incoming solar energy, while the atmosphere absorbs 23 per cent. The rest is reflected back into space. Natural processes ensure that the amount of incoming and outgoing energy are equal, keeping the planet’s temperature stable,

However, GHGs, unlike other atmospheric gases such as oxygen and nitrogen, are opaque to outgoing infrared radiation. As the concentration of GHGs in the atmosphere increases due to human-caused emissions, energy radiated from the surface becomes trapped in the atmosphere, unable to escape the planet. This energy returns to the surface, where it is reabsorbed.

Since more energy enters than exits the planet, surface temperatures increase until a new balance is achieved. This temperature increase has long-term climate impacts and affects myriad natural systems.

How to reduce GHG emissions?

Shifting to renewable energy, putting a price on carbon and phasing out coal are all important elements in reducing GHG emissions. Ultimately, stronger nationally determined contributions are needed to accelerate this reduction to preserve long-term human and environmental health.

[Note:-This story is a part of ‘Punascha Pruthibi – One Earth. Unite for It’, an awareness campaign by Sambad Digital.]