global temperature

Deadly Heatwaves On The Rise | Earth Wise

September 20, 2023 By EarthWise Leave a Comment

The European heatwave in the summer of 2003 resulted in at least 30,000 deaths with more than 14,000 in France alone. At the time, such a heatwave was considered to be a once-in-a-hundred-year event. But the warming climate is dramatically changing the odds for deadly heatwaves.

A new study by the ETH Institute in Zurich has found that the risk of fatal heatwaves has risen sharply over the past 20 years, and in the future, such extreme weather will become more frequent and heat-related excess mortality will increase, particularly in Europe. According to a paper published in Nature Medicine, more than 61,000 deaths in Europe could be blamed on the heat during the summer of 2022, which was the hottest summer on record for the continent. When the readings from this summer are analyzed, that record is likely to be surpassed.

Heatwaves lead to excess deaths due to dehydration, heat stroke, and cardiovascular collapse. They are particularly deadly for the elderly, the sick, and the poor. The ETH researchers analyzed comprehensive data from 748 cities and communities in 47 countries. They determined the relationship between increased temperature and excess mortality. Their models look at how excess mortality would develop with an average global temperature increase of 0.7 degrees Celsius (the value in 2000), 1.2 degrees (the value in 2020), and both 1.5 degrees (the limit sought by the Paris Agreement) and 2 degrees.

Even with the current global temperature, heatwaves that were a once-in-a-century event are now expected to occur every 10 years. With 2 degrees of warming, such heatwaves could happen every 2 to 5 years.

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Heatwaves are becoming more frequent and more deadly

Photo, posted July 22, 2009, courtesy of Matt McGee via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Why Was the Summer So Hot? | Earth Wise

September 4, 2023 By EarthWise Leave a Comment

Many places around the world have experienced extraordinary heat waves this summer. The 31 days of high temperatures 110 degrees or more in Phoenix is a prime example but many other places suffered from extreme and relentless heat. Why did this happen?

The overarching reason is climate change, which has warmed the Earth by 2.2 degrees Fahrenheit since the preindustrial era. This change on a global level is enough to make heatwaves far more likely. For example, the concurrent heatwaves in Europe and North America were 1000 times more likely to have occurred because of climate change.

But there hasn’t been a sudden increase in global temperature that would make this summer so much hotter. Instead, what really has happened is three other factors all came into play at the same time.

The first is the 2022 eruption of Hunga Tonga-Hunga Ha-apai, which is an underwater volcano in the South Pacific. That eruption did not produce much in the way of planet-cooling aerosols in the atmosphere. Instead, it vaporized huge amounts of seawater, sending water vapor into the atmosphere, which helps trap heat.

The second is a change in the amount of energy radiating from the sun. That actually rises and falls a small amount every 11 years. Currently, it is in the upswing and will reach its next peak in 2025.

Finally, there is the arrival of the El Niño in the Pacific, whose balmy ocean waters radiate heat into the air.

The combination of all these factors when added to the already warming climate is a recipe for temperatures to soar to uncharted highs. We can expect more heat waves, forest fires, flash floods, and other sorts of extreme weather.

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It’s Not Just Climate Change: Three Other Factors Driving This Summer’s Extreme Heat

Photo, posted February 27, 2017, courtesy of Giuseppe Milo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The World’s Hottest Day | Earth Wise

July 27, 2023 By EarthWise Leave a Comment

Early in July – for four days in a row – the average global temperature was the highest ever recorded. As many places around the world endured dangerous heatwaves, the average global temperature on the fourth of July reached 62.92 degrees Fahrenheit, the highest ever recorded by human-made instruments. On July 6th, the global temperature climbed even further to 63.01 degrees.

The average global temperature on an annual basis was about 56.7 degrees from the 1880s through the 1910s. Temperatures rose a bit after that but ended up about 57.2 degrees until the 1980s. After that, temperatures have risen fairly steadily as heat-trapping gases have accumulated in the atmosphere driving the current average above 58 degrees.

Global temperatures have only been directly measured since the mid-20th century. There are proxy measurements from sources like tree rings, ice core samples, glacier measurements, and more that indicate that the recent readings may be the warmest days the earth has seen in millennia.

Average global temperature is determined using temperature readings at thousands of locations on both land and sea across the entire planet. Those readings are compared with average temperatures at those locations for the date and the difference (known as the temperature anomaly) used to calculate a global average.

With the recent arrival of the El Niño in the Pacific Ocean, it is likely that the warming already being driven by greenhouse gas accumulation will intensify further.

In a summer already marked by extreme heatwaves in many locations, having the entire planet 4 or 5 degrees hotter than normal is a very big deal and most certainly not a record to celebrate.

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Earth reaches hottest day ever recorded 4 days in a row

Photo, posted October 29, 2008, courtesy of Darek via Flickr.

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An Unwanted Temperature Threshold Is Approaching | Earth Wise

July 3, 2023 By EarthWise Leave a Comment

According to the World Meteorological Organization, there is a 66% chance over the next five years that the Earth’s global temperature will exceed 1.5 degrees Celsius above pre-industrial levels for at least one year.

A combination of the continued accumulation of greenhouse gases in the atmosphere along with a looming El Niño condition will contribute to surging temperatures. The WMO also reports that there is a 98% likelihood that at least one of the next five years will be the warmest on record and that the five-year period as a whole will be the warmest on record.

Reaching or surpassing the 1.5-degree threshold may only be temporary but would be the strongest indication yet of how quickly climate change is accelerating. The 1.5-degree point is considered by many scientists to be a key tipping point, beyond which the chances of extreme flooding, drought, wildfires, heatwaves, and food shortages could increase dramatically.

The world has already seen about 1.2 degrees of warming as we continue to burn fossil fuels and produce enormous quantities of greenhouse gas emissions. As recently as 2015, the WMO put the chance of breaching the 1.5-degree threshold as close to zero.

It is important to understand that the 1.5-degree temperature increase is an average for the entire planet. Many individual locations around the world have been experiencing tremendously greater amounts of warming with record-breaking temperatures.

The 1.5-degree threshold is important, but it is not itself a tipping point. There is still time to reduce global warming by moving away from fossil fuels and towards clean energy. But the clock is ticking and so far, the world is not showing any urgency.

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‘Sounding the alarm’: World on track to breach a critical warming threshold in the next five years

Photo, posted May 20, 2015, courtesy of Kevin Gill via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Hottest September | Earth Wise

November 5, 2020 By EarthWise Leave a Comment

Here’s a news item that is like many other recent news items: September 2020 was the hottest September since 1880, according to the National Oceanic and Atmospheric Administration. The warm September is a part of a year that so far is poised to be at least the second hottest year in the 141-year climate record.

The ten warmest Septembers on record have all occurred since 2005, and the seven warmest Septembers have occurred in the past seven years.

So far, the year-to-date average global temperature has been the second warmest on record, being just 0.07 degrees Fahrenheit lower than the record year-to-date temperature set in 2016. Expectations are that 2020 will end up somewhere among the three warmest years on record for the globe.

September was warm in many places around the world. California and Oregon had their warmest September ever. Europe had its warmest September on record, Asia had its second warmest September on record as did Australia and South America.

So far, it has been the hottest year-to-date on record in Europe, Asia, and the Gulf of Mexico. No land or ocean areas anywhere had record-cold year-to-date temperatures.

Global temperatures represent an average over the entire surface of the planet. The fact that the global temperature is now nearly one Celsius degree above the 20th century average means that a vast amount of heat has been added in order to warm all the oceans, atmosphere, and land by that much. So, every uptick in global temperature is a big deal.

Meanwhile, the average Arctic sea ice coverage for September was the second smallest on record. The 14 smallest minimum annual sea ice extents have all occurred in the past 14 years.

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Earth just had its hottest September on record

Photo, posted September 2, 2020, courtesy of Tim Vrtiska via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Hottest Month Ever

August 27, 2019 By EarthWise Leave a Comment

European climate researchers announced that July was the hottest July ever recorded and since July is generally the hottest month of the year, it was indeed the hottest month ever recorded. It just barely beat out the previous record set in July 2016. There are multiple agencies that track temperatures around the world, and it is possible that some of them may report slightly different results.

But whatever July’s ultimate ranking is, it is part of a long-term trend. The past five years have been the hottest on record. The 10 hottest years ever recorded have all occurred during the past twenty years.

This June was also the warmest on record, and the previous five months were all among the four warmest for their respective months. All of that puts this year on track to be in the top five warmest years, or perhaps the hottest ever.

The highest above-average conditions were recorded across Alaska, Greenland, and large areas of Siberia. Large parts of Africa and Australia were warmer than normal, as was much of central Asia. New temperature records were set in Belgium, the Netherlands, and Germany with temperatures over 104 degrees Fahrenheit. Great Britain saw an all-time record of 101.7 degrees and Anchorage, Alaska stayed above 79 degrees for a record six days in a row.

Wildfires have raged across the Russian Arctic, India has suffered heatwaves and severe water shortages, and Japan saw more than 5,000 people seek hospital treatment during a heatwave.

While scientists cannot directly link any particular heatwave to climate change, the trend for new heat records is likely to continue and accelerate unless we do something about curbing greenhouse gas emissions.

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How Hot Was July? Hotter Than Ever, Global Data Shows

Photo, posted May 25, 2019, courtesy of Jakob Montrasio via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Record European Heatwave

August 1, 2019 By EarthWise Leave a Comment

Sahara Desert winds blasted Europe in June, especially during a five-day heatwave that set many records. Between that and weather elsewhere, June was not only one of the hottest ever for that continent, but also for the world as a whole.

In Europe, the average temperature was about 5 degrees Fahrenheit above the June average of a century ago. The global temperature was nearly 2 degrees Fahrenheit higher.

The European heatwave broke temperature records in France, Switzerland, Austria, Germany, and Spain. A temperature above 114 degrees was recorded near the French city of Nîmes.

The intense heat lead to wildfires in Spain and Germany, and widespread disruption across Europe. Undoubtedly, the heatwave has caused many premature deaths, but it will take some time to compile those statistics. The European heatwave of 2003 caused more than 70,000 premature deaths.

According to calculations by climate scientists, the record-breaking heatwave in June was made at least 5 and as much as 100 times more likely by climate change. Global heating caused by the carbon emissions from burning fossil fuels and other human activities means that heatwaves are becoming more probable and severe. So-called attribution studies estimate how much more likely and severe such events are.

The researchers used temperature records stretching back to 1901 to assess the probability of a heatwave last month and in the past. They also examined climate change models to assess the impact of global heating. More than 230 attribution studies to date around the world have found that 95% of heatwaves were made more likely or worse by climate change.

It was the hottest June on record in Europe by a country mile and there are likely to be more months like it in the future.

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Climate Change Made Last Month’s European Heatwave At Least Five Times More Likely

Photo, posted February 13, 2018, courtesy of Guilhem Vellut via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.