Tag Archives: Climate warming

As global warming surges, so does the hot summer weather

Extreme weather events during the summer such as heatwaves, droughts and rainy periods could last longer in the Northern Hemisphere, according to a new paper which warns over the consequences of climate change.

Credit: Flickr

Heat and rainfall extremes have intensified over the past few decades and this trend is projected to continue with future global warming. Rises in extreme heat and rainfall can have impacts on human health and agriculture, and on the environment, including an increased risk of wildfires. As the effects of global warming continue to unfold, this extreme weather will become more and more common, even if global warming is limited to 2ºC, as is currently stipulated in the Paris Agreement.

“Global warming is already increasing the frequency and intensity of heat and rainfall extremes, as well as the duration of heat waves, and these trends are projected to continue with future warming,” the authors of the new study write.

Extreme weather events are often measured in terms of intensity or frequency, but often it is the duration, or persistence, of events that lead to the most severe impacts, which are already visible across the globe.

Peter Pfleiderer and colleagues carried out a multi-model analysis of the persistence of local weather conditions in the Northern Hemisphere mid-latitudes. If temperatures rise by 2ºC relative to pre-industrial levels, hot weather periods of longer than two weeks could increase by around 4% relative to the recent past across the mid-latitudes, according to the research.

“Our analysis shows that summer weather becomes more persistent, with global warming increasing risks associated with long-lasting heat waves, droughts, rain periods and compound hot–dry extremes,” the authors said.

The authors said Eastern North America could see persistent hot and dry spells rise by up to 20%. At the same time, heavy rainfall lasting for one week or more, which can lead to flooding, could increase by 26% on average for the mid-latitudes under a 2°C scenario. When considering the projected warming of 1.5°C, the authors found these increases were largely avoided.

“In conjunction with the projected intensification of heat and rainfall extremes, an increase in persistence can substantially worsen the effects of future weather extremes,” the authors said.

Countries agreed under the Paris Agreement to keep the increase in global average temperature to well below 2°C above pre-industrial levels while aiming at 1.5º C if possible. In other words, if we can maintain the planet’s warming below 1.5º C, we could spare ourselves a lot of trouble — but this means global emissions will have to peak as soon as possible.

Nevertheless, with the current country commitments, the temperature would increase between 3º and 4ºC instead of the required 2ºC under the Paris Agreement, according to the most recent analysis.

The study “Summer weather becomes more persistent
in a 2 °C world” was published in Nature Climate Change.

Methane.

One research team proposes swapping atmospheric methane for CO2, and it might be a good idea

A relatively simple but counterintuitive approach aims to fight climate change — by actually increasing CO2 emissions.

Methane.

Image via Pixabay.

Fighting climate warming with greenhouse emissions might sound like it won’t work, because it wouldn’t. The team that authored this study, however, doesn’t just aim to increase CO2 levels in the atmosphere. Rather, it proposes that we degrade methane, a much more potent greenhouse gas, into CO2 — the swap, they write, would be a net benefit for world climate.

The study proposes zeolite, a crystalline material that consists primarily of aluminum, silicon, and oxygen, as a key material to help us scrub methane emissions.

The lesser of two evils

“If perfected, this technology could return the atmosphere to pre-industrial concentrations of methane and other gases,” said lead author Rob Jackson, the Michelle and Kevin Douglas Provostial Professor in Earth System Science in Stanford’s School of Earth, Energy & Environmental Sciences.

Much more relevant to the current situation, the team notes, is that this process is also profitable. Boiled down, the idea is to take methane from sources where it’s difficult or expensive to eliminate — from cattle farms or rice paddies, for example — and degrade it into CO2.

Methane concentrations in the atmosphere are almost two-and-a-half times higher today than before the Industrial Revolution, the team explains. There’s a lot less methane than CO2 in the air, granted, but methane is 84 times more potent than CO2 as a climate-warming gas over the first 20 years after its release. Finally, some 60% of atmospheric methane today is directly generated by human activity.

Most climate strategies today focus on CO2, which is understandable. It’s the largest (by quantity) greenhouse gas we emit, and it’s easy to relate to — we breathe out CO2, cars belch out CO2, factories do too, and plants like to munch on it. But scrubbing other greenhouse gases, particularly methane due to its enormous greenhouse effect, could be useful as a complementary approach, the team explains. Furthermore, there’s just so much CO2 already floating around — and we keep pumping it out with such gusto — that CO2-removal scenarios often call for billions of tons to be removed, over decades, which would still not get us to pre-industrial levels

“An alternative is to offset these emissions via methane removal, so there is no net effect on warming the atmosphere,” said study coauthor Chris Field, the Perry L. McCarty Director of the Stanford Woods Institute for the Environment.

Methane levels could be brought back down to pre-industrial levels by removing about 3.2 billion tons of the gas from the atmosphere, the team notes. Converting all of it into CO2 would be equivalent to a few months of global industrial emissions, which is relatively little, but would have an outsized effect: it would eliminate approximately one-sixth of all causes of global warming to date.

So why then didn’t anybody think of this before? Well, the thing is that methane is hard to scrub from the air because its overall concentrations are so low. However zeolite, the team explains, is really really good at capturing the gas due to its “porous molecular structure, relatively large surface area and ability to host copper and iron,” explains coauthor Ed Solomon, the Monroe E. Spaght Professor of Chemistry in the School of Humanities and Sciences. The whole process could be as simple as using powerful fans to push air through reactors full of zeolite and catalysts. This material can then be heat-treated to form and release carbon dioxide gas.

Now let’s talk money. If market prices for carbon offsets rise to $500 or more per ton this century as predicted by most relevant assessment models, the team writes, each ton of methane removed from the atmosphere could be worth more than $12,000. A zeolite reactor the size of a football field could thus produce millions of dollars a year in income while removing harmful methane from the air. This is very fortunate as, in my experience, nothing motivates people to care about the environment quite like making money from saving it.

In principle, the researchers add, the approach of converting a more harmful greenhouse gas to one that’s less potent could also apply to other greenhouse gases.

The paper “Methane removal and atmospheric restoration” has been published in the journal Nature Sustainability.