This year, cold countries like Canada experienced heatwaves causing temperatures to soar to nearly 50° C, due to which hundreds perished and thousands were rendered homeless. Heavy rains and floods in Germany, Belgium wreaked havoc.
So have the floods in Maharashtra, Kerala and Karnataka. It is evident that these extreme weather conditions that have affected many parts of the world have been caused by climate change.
A recent report by the Intergovernmental Panel on Climate Change (IPCC) has issued its strongest warning yet. If no action is taken, global temperatures could rise by 1.5°C or 2°C even before 2040. This could cause irreversible damage, spelling out more weather-related calamities, the report said.
Global warming is caused by the increasing amount of gases like carbon dioxide mainly resulting from human activity. Gases like carbon dioxide hang on in the atmosphere for several decades, trapping the infrared waves from the irradiating solar radiation.
The increase in trapped heat also evaporates more water from oceans, seas, etc and the water vapour traps heat. This explains why cloudy days are warmer than when the skies are clear. However, water vapour quickly condenses as it cools and does not stay for decades in the atmosphere, like carbon dioxide.
The amount of CO2 has considerably increased since the start of the industrial revolution.
The burning of fossil fuels, transportation, mainly on petroleum products, aviation and a whole host of perennial industrial activities pump around a whopping 50 gigatonnes of CO2 annually into the atmosphere.
All of our everyday appliances and devices consume power and disperse heat, the global power consumption of 20 Terawatts (1 Terawatt is a trillion watts); most of the heat is produced by fossil fuels.
Not the only cause
Carbon dioxide is however not the only global warming gas. Methane is more potent in this regard. Organic waste from animals and agriculture releases methane. For instance, 100 cows produce six tonnes of methane. T
hen there are other larger sources like the Greenland ice sheets which release tonnes of methane as they melt due to global warming, so also the Siberian permafrost. Unlike CO2, methane does not remain for a long time in the atmosphere.
Another common gaseous substance --Nitrous Oxide--is 300 times more potent than CO2 in heating the atmosphere. Like CO2, it hangs around in the atmosphere for a long time, spending about 120 years in the air before disintegrating. Moreover, it also depletes the ozone layer.
In short, the climate impact of laughing gas (N2O) is not a laughing matter! The IPCC panel estimated that nitrous oxide could comprise nearly 10% of greenhouse gases and three-quarters of it comes from agriculture which accounts for nearly a fourth of climate-warming emissions, much of the emissions is from nitrous oxides and not CO2.
Apart from indiscriminate industrialisation, humans have tipped the natural nitrogen cycle. The Haber-Bosch process led to the synthesis of ammonia, leading to a large production of ammonium fertilisers. This increased global food production but upset the natural nitrogen cycle of plants. The amount of nitrous oxide is also increasing in the atmosphere.
More potent greenhouse gases
While there is scope for getting more power from renewable sources of producing electricity like wind power, this has led to the production of an even more potent greenhouse gas, Sulphur hexafluoride or SF6 which is used in wind turbines. It is used as an insulator and interceptor agent in many power generating appliances.
However, the dismal fact is that SF6 has more than 20,000 times the global warming potential than CO2. Moreover, it is stable and has an extended lifetime of 3,000 years, making it the most potent chemically reacting greenhouse gas.
The concentration of this gas is increasing, though its presence contributes only a small fraction to global warming now.
Although CO2 is the most well-known culprit, there are other more potent gases lurking in the background and their presence is growing.