Methane emissions: did we just ignore a huge climate threat?

#methane is the main #greenhouse gas produced by human activities. It’s also the second most abundant gas in the atmosphere, after carbon dioxide (CO₂). But methane doesn’t stay there—it is a very powerful greenhouse gas. The Earth receives about 100 billion tonnes of CO₂ per year from the atmosphere—about half of that comes from natural processes like photosynthesis, and half comes from human activities like agriculture and fossil fuel use. Methane emissions produced by these human activities add up to about 80 billion tonnes per year. That’s 11% of all greenhouse gases emitted into the atmosphere, and it’s expected to increase as we continue to burn fossil fuels at increasing rates. Unfortunately, methane is also a very short-lived greenhouse gas: it breaks down quickly in the atmosphere and disappears before it can do any damage. This makes capturing methane for later storage or use more difficult than capturing CO₂. Methane may seem like a silly cause for worry about climate change and global warming, but methane is an even bigger danger than people realize—and ignoring it will only make things worse.

Why is methane so dangerous?

Methane is a very powerful greenhouse gas. It’s been estimated that methane has more than 25 times the warming power of CO₂ over a 100-year time frame. That’s because methane breaks down faster in the atmosphere, so it doesn’t hang around as long. Methane also stays in the atmosphere for about 12 years, which means one big methane event can have a big impact on climate change and global warming over the next few decades. Methane also has another nasty feature—it helps to move heat from the tropics towards the poles. This happens because there are more molecules of methane in the tropics than in higher latitudes, balancing out temperatures at different latitudes so that they don’t get too hot or too cold. But when we increase our rates of burning fossil fuels, that balance changes and more heat goes into the tropics while less heat goes to higher latitudes as more methane is broken down in these regions. The extra heat going into high latitudes makes them warmer and drier—which can trigger feedback loops called ‘positive feedback cycles’ that accelerate global warming even further. If you want to avoid this vicious cycle and protect yourself against climate change and global warming, you need to reduce your emissions of methane now.

What do we know about methane emissions?

According to the United States Environmental Protection Agency, humans in the United States produce almost 1.6 million tonnes of methane per year—a number that has been increasing dramatically over the years. That’s a lot of methane. Methane emissions are also not spread evenly across the country. The West Coast is an epicenter of these emissions with 10% of all human-related methane produced in this region alone. With such high numbers, it’s really important for us to know if we are doing everything we can to cut back on these emissions.

Causes of methane #emissions

Methane is emitted during the natural process of decomposing organic material in landfills, manure storage and rice paddies. It’s also emitted when gas is extracted from oil wells, as well as when waste management activities like landfilling produce large amounts of methane that can’t be captured. In addition, methane emissions are caused by dairy cow burps, cows digesting food and digesting their own feed. Methane emissions are currently highly underestimated because the main method for measuring carbon dioxide emissions is from fossil fuel burning. With changes to our method of measuring methane emissions, we'll be able to more accurately measure how bad things have become. Methane from animal agriculture accounts for 30% of human-caused methane emissions—a major cause of climate change and global warming.

The global warming potential of methane

Methane is the second most important greenhouse gas to global warming, after CO₂. Methane has a global warming potential that is 21 times greater than CO₂ on a 20-year time scale, and it’s also 84 times greater on a 100-year time scale. It’s not just the magnitude of methane’s global warming potential that makes it so dangerous—it’s how quickly methane disappears from the atmosphere. In contrast to CO2, which can stay in the atmosphere for centuries, methane breaks down in only about 12 years.

How much methane does the atmosphere currently contain?

The current atmospheric concentration of methane is about 1.45 billion tonnes, which is about 25% higher than the pre-industrial levels. When we burn fossil fuels, it makes its way into the atmosphere and adds to this figure. The amount of methane in the atmosphere has been increasing steadily since measurements began in 1978. If you're worried about climate change and global warming, there's a good chance that methane emissions are one of your top concerns. Methane can be captured at various stages: during production and storage, or from landfill sites or old oil wells after drilling. Capturing it reduces its lifetime in the atmosphere and also provides a much cleaner alternative to burning fossil fuels for energy production by using methane for fuel instead.

Future projections for global warming potential of methane emissions

Methane is a serious threat to our planet, and the environmental effects of human activities are already evident. The future projections for global warming potential of methane emissions in the next century are alarming. This is because methane has a lifetime of only about 12 years in the atmosphere. We need to start taking action now with methods like carbon capture and storage (CCS) if we want to stave off this looming threat. Among other consequences, melting icecaps will cause sea level rise and more severe storms, including hurricanes and typhoons that will have larger impacts on coastal areas. Many coastal cities will be at risk for inundation from storm surge—including New York, Miami, Houston, Seattle, Manila, Mumbai, Shanghai, Jakarta, and Tokyo.

Summary

Methane is one of the most powerful #greenhouse gases. And it's not just CO2 that contributes to #climatechange change, methane accounts for 11% of all #global greenhouse gas emissions. Methane isn't a big concern because it breaks down quickly and disappears, but studies have shown that ignoring methane could lead to disastrous effects on our planet's future. Methane's short-lived nature makes capturing and storing methane difficult. The Earth receives about 100 billion tonnes of CO₂ per year from the atmosphere—about half of that comes from #natural processes like photosynthesis and plants, and half comes from human activities like agriculture and fossil fuel use. But methane emissions produced by these human activities add up to about 80 billion tonnes per year--11% of all greenhouse gases emitted into the #atmosphere. This means that there are more than 3 times as many GHG emissions coming from trapping methane than there are CO2 emissions--and it's expected to increase as we continue to burn fossil fuels at increasing rates.