Climate Change Driving Surge in ‘Day-Night Hot Extremes’ in Northern Hemisphere
By Daisy Dunne
Deadly "day-night hot extremes" are increasing across the northern hemisphere due to climate change, a new study finds.
And the number of people exposed to such events, also known as "compound hot extremes," is likely to increase "several-fold" as temperatures continue to climb in the coming decades, the study authors tell Carbon Brief.
If global temperatures reach 2 C — the upper limit set by countries in the Paris agreement — the frequency of compound hot extremes could more than double across the northern hemisphere, when compared to 2012, the research finds.
However, if greenhouse gas emissions are not curbed, compound hot extremes could become eight times more frequent by the end of the century.
The study sets out "clear evidence" that human-caused climate change is leaving its mark on extreme heat events, another scientist tells Carbon Brief.
Day and Night
The new study, published in Nature Communications, looks specifically at "compound hot extremes" — a 24-hour period in summer where hot daytime temperatures are followed by similar nightime temperatures. (Temperatures are considered "hot" if they are in the top 10% of temperatures experienced by a region from 1960-2012.)
These kinds of events pose a particularly high danger to human health, explain study authors Dr Yang Chen, a climate extremes scientist from the Chinese Academy of Meteorological Sciences, and Dr Jun Wang, a climate and meteorological scientist from the Institute of Atmospheric Physics in China. In a joint interview, they tell Carbon Brief:
Simply put, compound hot extremes deprive humans of the valuable chance of relief, which could have been provided by the 'cooling-off' effects of a nighttime low.
Such conditions occurred during the 2003 summer heatwave in Europe, which saw 70,000 deaths across 16 countries, the authors say. Another example is the 1995 Chicago heatwave, which led to more than 700 heat-related deaths in just five days.
The study is the first to present "a complete storyline on compound hot extremes" — investigating how they have changed, the role of climate change in this and how they might increase in the future, the authors say.
The results show that compound hot extremes "are significantly increasing and will continue to increase in frequency and intensity" across the northern hemisphere, say Chen and Wang:
These increases in heat hazards will translate into several-fold increases in population exposure to them. The rise of anthropogenic emission of greenhouse gas emissions is to blame for these increases.
For the first part of their study, the authors analysed the "fingerprint" of human-caused climate change on compound hot extremes to date. To do this, they conducted an "attribution" analysis.
This involves using climate models to produce two sets of simulations: one including all the factors that affect the climate, including human-caused greenhouse gas emissions, volcanic eruptions and solar variability, and one including all of these factors except for greenhouse gas emissions.
The researchers then compared the frequency and intensity of compound hot extremes in both of these scenarios.
They found that only the scenario including human-caused greenhouse gas emissions could closely reproduce the pattern of compound hot extremes observed from 1960 to 2012. In their research paper, the authors write:
We find that the summer-mean warming over 1960-2012 largely dictates the past increases in frequency and intensity of compound hot extremes during that period in both observations and simulations.
The maps below show observed changes in summertime compound hot extreme frequency (left) and intensity (right) across the northern hemisphere from 1960-2012.
The left-hand map shows changes in the number of compound hot extreme days per decade (yellow to red for increases; light to dark blue for decreases), while the right-hand map shows changes in the average temperature of compound hot extremes per decade (same color scale).
Contributions from changing temperature mean and variability. Wang et al. (2020)
The map shows that increases in the frequency and intensity of compound hot extremes are widespread across the northern hemisphere, with parts of continental Europe and China particularly affected.
(Gaps in the data prevented the researchers from analysing changes in the most southern parts of the northern hemisphere, the authors say in their research paper.)
While the global pattern of increases is best explained by human-caused global warming, it is possible that some regional differences may be explained by other factors, the authors say.
For example, the drying of soils could help to explain local variation of heat extremes, the authors say in their research paper.
This is because dry soils accumulate heat during the day and release it at night, Wang and Chen say, making night hot extremes and, therefore, compound hot extremes, more likely.
The authors also used climate models to project possible future changes to compound hot extremes until 2100. They investigated two scenarios: one "intermediate mitigation" pathway with moderately high greenhouse gas emissions ("RCP4.5") and one with very high greenhouse gas emissions ("RCP8.5").
Within each emissions scenario, they also looked at the changes to compound hot extremes expected if the world reaches 1.5 C and 2 C of global warming, which are the temperature limits set by the Paris agreement.
The charts below show the average expected change in the number of summertime compound hot extreme days (purple line), as well as independent hot days (blue line) and independent hot nights (turquoise line) across the northern hemisphere under RCP4.5 (top) and RCP8.5 (bottom) until 2100. (Compound extremes are where a hot day is followed by a hot night, whereas an "independent hot day" is when a hot day is not followed by a hot night.)
On the charts, red circles point out when the temperature limits of 1.5 C and 2 C will be breached in each scenario. The bottom chart also highlights when 4C could be breached. The various data points represent results from different climate models.
(It is worth noting that events are considered to be compound or independent. So, a 24-hour period where a hot day is followed by a hot night would be considered a compound extreme, but not an independent hot day or hot night.)
Constrained projections of summertime hot extremes. Wang et al. (2020)
The results show that the average number of compound hot extreme days across the northern hemisphere in summer would more than double if temperatures reach 2 C, when compared to 2012.
Keeping temperatures at 1.5 C could see five fewer compound hot extreme days across the northern hemisphere, on average, when compared to 2 C, the research adds.
If greenhouse gas emissions are extremely high (RCP8.5), the number of summertime compound hot extremes could increase eight-fold by 2100, when compared to 2012, the results show.
The charts also show that compound hot events are expected to increase at a much more rapid rate than independent hot day or hot night events.
This is chiefly because climate change is known to have a larger effect on nightime temperatures than daytime temperatures, the authors say.
Therefore, as the chances of hot nights become higher, the chances of compound hot events also increase — and, so, the chances of a hot day or night occurring independently decreases, explain Chen and Wang.
The findings reinforce "the urgency in reducing emission of greenhouse gases" for policymakers, say Chen and Wang:
We should keep the point in mind that as the globe warms, future summers are increasingly dominated by compound hot extremes and become more uncomfortable. Namely, a hot day accompanied by a hot night without a relief window for humans might become a 'new norm'. As a result, vigilance against excess heat should be kept through day and night.
I think the main take home message from this study is that we should use consecutive day-night hot extremes as a major heat-health indicator for policymaking, as compound hot extremes are projected to have larger future increases in frequency and intensity then hot days or nights.
The findings produce "clear evidence" that human-caused climate change is leaving its mark on extreme heat events, says Prof Peter Stott, who leads on climate monitoring and attribution at the Met Office Hadley Centre. Stott, who was also not involved in the research, tells Carbon Brief:
I don't find the conclusions of the study very surprising, but I do like the way the authors have comprehensively set out the implications – the clear evidence that the changes to date are driven by human emissions and the clear evidence that future changes will result in significant increases in the frequency and intensity of these compound extremes worldwide.
Reposted with permission from Carbon Brief.
- What Climate Crisis Will Do to 3 Major American Cities by 2100 ... ›
- 57 Dead, 18,000 Hospitalized in Japan Heat Wave - EcoWatch ›
- Why Night Can Be the Most Dangerous Time During Heat Waves ... ›
- 36 Die in India Heat Wave, Delhi Records Its Highest All-Time ... ›
In a dramatic rescue captured on camera, a Florida man ran into a pond and pried open an alligator's mouth in order to rescue his beloved puppy, all without dropping his cigar.
- 'He had green eyes': Florida man will paint alligator that attacked him ›
- Florida alligator attack: A woman was attacked by a 10-foot alligator ... ›
- Weird presidential pets include alligator, tiger cub, dog named Satan ... ›
- Alligators make terrible pets: 'You're basically dealing with a dinosaur.' ›
EcoWatch Daily Newsletter
Jean-Marc Neveu and Olivier Civil never expected to find themselves battling against disposable mask pollution.
When they founded their recycling start-up Plaxtil in 2017, it was textile waste they set their sights on. The project developed a process that turned fabrics into a new recyclable material they describe as "ecological plastic."
Mounting Piles of Waste<p>It is not only the streets of Chatellerault where pandemic pollution is piling-up, but also the world's beaches and oceans. Once there, they can take up to 450 years to degrade and disappear.</p><p>Esther Röling, co-organizer of the annual Adventure Clean Up Challenge held on Hong Kong Island, has seen this waste firsthand. In October the sports challenge pitted teams against one another in a competition to remove trash from 13 hard-to-reach coastal areas around the city.</p><p>They find tons of both disposable and reusable masks, said Röling. "You wonder how it ended up there. Was it just thrown on the ground? Or was it in a garbage bag that broke open?"</p><p>Almost 10,000 kilometers away in Antibes on the sunny French Riviera, it's a similar picture. For the past few months, divers and clean-up volunteers working with an ocean clean-up non-profit called Operation Mer Propre have been collecting an increasing number of masks found on land and in the sea.</p><p>"Since the beginning of the lockdown when we started to count, we've reached 800, 900, [and now in total] 1000 masks," said co-founder Joko Peltier. </p><p>According to <a href="https://unctad.org/news/growing-plastic-pollution-wake-covid-19-how-trade-policy-can-help" target="_blank">UN estimates</a>, up to 75% of all coronavirus-related plastic could end up as waste in oceans and landfills.</p>
The Limits of Recycling<p>Yet not all are convinced the recycling of this waste is possible on a global scale. </p><p>"What those citizen groups are doing is really beneficial but once they collect it, it should just go to a landfill or an incinerator. They shouldn't necessarily expect it to get recycled," said Jonathan Krones, an industrial ecologist and visiting assistant professor of environmental studies at Boston College.</p><p>That's because mask recycling programs like Plaxtil are few and far between and most don't have the benefit of a readily adaptable production process. </p><p>Even in countries with solid recycling infrastructure, he says, the system is designed to separate out specific types of waste like bottles or cardboard.</p><p>"I imagine that it would be technically feasible to develop a separation process to filter out masks, but there simply aren't enough of them to make that economical," he said.</p><p>Collection is a big hurdle, he adds. Since each mask only weighs a fraction of a gram and they're scattered on roads or mixed with other trash, it is difficult and costly. </p><p>"You need a lot of raw material of the right quality to make investing in the recycling technology and the recycling system worthwhile," he said.<span></span><br></p>
Hemp, Sugar Cane and Sustainable Alternatives<p>Some projects are instead addressing the material used to make masks.</p><p>French company Geochanvre have created a mask made primarily from hemp, while in Australia, researchers at the Queensland University of Technology are experimenting with a disposable product made from agricultural waste. </p><p>Biodegradable options are exciting alternatives to reduce the fossil fuels needed for the creation of plastic-based masks, said Krones, but they don't absolve the wearer from the responsibility of what happens afterwards. </p><p>Bio-based masks often need their own composing solutions, he explains, because in landfill they can produce high amounts of the greenhouse gas methane when anaerobic bacteria feeds on the organic material. Methane is known to be significantly more potent than carbon dioxide.</p><p>"I think as long as we have in our mind that we want to have disposability, we're going to have to wrestle with a variety of different sorts of environmental tradeoffs," he said, adding that reusable, fabric masks are the best option available to most people.</p><p>Precimask is developing a clear face covering with an optional visor made from hard plastic, designed to be long-lasting.<br></p><p>Air enters either side of the cheeks through a technology normally found in pool filters and car exhaust systems, said company spokeswoman Juliette Chambet.</p><p>"We wanted to make ceramic-based filters that would be washable and cleanable, which would allow them to be reused as many times as desired without having to buy a new consumable or produce waste," she said. </p><p>Ultimately, encouraging mask wearers to think about the entire lifecycle of a mask is key, explains Neveu. </p><p>"We want people who put on the masks to realize that they are also responsible for the waste, he said. "It's not inevitable that this [pandemic] will become an environmental catastrophe.</p><p><em>Reposted with permission from </em><em><a href="https://www.dw.com/en/covid-19-recycling-pollution-trash-pandemic/a-55707817" target="_blank">Deutsche Welle</a>.</em><a href="https://www.ecowatch.com/r/entryeditor/2649032193#/" target="_self"></a></p>
- Coronavirus Plastic Waste Polluting the Environment - EcoWatch ›
- Scuba Divers Make Face Masks out of Recycled Ocean Plastic ... ›
By Bret Wilkins
In a year in which the United States has already suffered 16 climate-driven extreme weather events causing more than $1 billion in economic damages, and as millions of American workers face loss of essential unemployment benefits due to congressional inaction, a report published Monday reveals the Trump administration has given fossil fuel companies as much as $15.2 billion in direct relief — and tens of billions more indirectly — through federal COVID-19 recovery programs since March.
- 'We Need People's Bailout, Not Polluters' Bailout': Climate Groups ... ›
- Corporate Polluters Have Received Tens of Millions in PPP Loans ... ›
- Trump Bails Out Oil Industry, Not U.S. Families, as Coronavirus ... ›
- Former Federal Reserve Governor Rebukes Fed for Fossil Fuel Bail ... ›
By Ashia Aubourg
As Thanksgiving approaches, some Indigenous organizations and activists caution against perpetuating further injustices towards Native communities. Indigenous activist Mariah Gladstone, for example, encourages eaters to celebrate the harvest time in ways that do not involve stereotypes and pilgrim stories.
- Why Face Masks Belong at Your Thanksgiving Gathering + 7 Things ... ›
- Reasons to Be Thankful — 8 Food and Farm 'Good News' Stories ... ›
- Why I'm Going to Standing Rock for Thanksgiving - EcoWatch ›
By Alex Middleton
Losing weight and reducing fat is a hard battle to fight. Thankfully, there are fat burner supplements that help you gain your target body and goal. However, how would you know which supplement is right for you?