BENGALURU, India (AP) — Greenhouse gases, like carbon dioxide, methane, nitrous oxide and fluorinated gases, are all warming the planet. What are the main human activities that cause them?
Most of these planet-warming gases are spewed out for energy, as coal, oil and gas still provide a large portion of the world’s needs. Energy for industries like steel and iron, electricity to turn on lights in homes and buildings, and gas to power cars, ships and planes all pump carbon dioxide into the atmosphere. air if they do not come from renewable sources.
Agricultural practices, such as deforestation and animal husbandry, account for almost a fifth of global emissions. Waste such as landfills, leaks from oil and gas extraction, and processes such as cement manufacturing that produce carbon dioxide as a byproduct also emit greenhouse gases.
EDITOR’S NOTE: This story is part of an ongoing series that answers some of the most fundamental questions about climate change, the science behind it, the effects of global warming, and how the world faces it.
Carbon dioxide accounts for more than three quarters of all human-made greenhouse gases. Methane, mainly from agriculture, coal mining and disturbing peatlands and wetlands that naturally trap the gas, accounts for about 16% of greenhouse gases in the atmosphere. Nitrous oxide from agricultural practices and fluorinated gases from refrigerants make up the rest.
Some of these gases stick around longer than others. It is estimated that carbon dioxide can stay in the air for 200 years or more, so coal burned in the early industrial age would still warm the planet today. In contrast, methane, which is about 81 times more potent in the short term than carbon dioxide, persists in the atmosphere for about a dozen years.
“Global warming is caused by the buildup of greenhouse gases over time in the atmosphere, which creates a higher concentration,” said Professor Shobhakar Dhakal, one of the lead authors of a report of the Intergovernmental Panel on Climate Change.
“Historical emissions, which refer to emissions accumulated over time, are important to consider,” he added.
But humans still expel large amounts of carbon into the air today. Emissions between 2010 and 2019 were higher than any previous decade in human history.
Net emissions from 1850 to 2019 were about 2,400 gigatons of carbon dioxide. Of these, 58% occurred between 1850 and 1989 – a period of 139 years – with the remaining 42% being created between 1990 and 2019 – just 29 years, according to the latest IPCC estimates. About 17% of emissions since 1850 occurred between 2010 and 2019.
Rapidly growing urban sprawl around the world is responsible for more greenhouse gases being dumped into the air each year, according to the report.
“We are still in the age of fossil fuels as a global society,” said Professor Jan Christoph Minx, lead author of the IPCC report and a German-based climatologist. “We often forget that we have yet to successfully reverse the mega trend of over 250 years of growth in global emissions.”
Minx said any reductions by making systems more efficient or changing energy sources to more sustainable ones have been less than increases resulting from higher global activity levels in industry, energy supply, transport, agriculture and buildings.
“The first step is to peak emissions and enter an era of reduced emissions where every year we emit less and less greenhouse gases around the world,” he added.
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