Globall 2022 is currently the four highest year for wildfire carbon emissions.
Blazes that have torched tens of thousands of hectares of forest in France, Spain and Portugal have made 2022 a record year for wildfire activity in southwestern Europe, the EU’s satellite monitoring service said Friday.
Amid a prolonged heatwave that saw temperature records tumble, the Copernicus Atmosphere Monitoring Service (CAMS) said that France had in the last three months reached the highest levels of carbon pollution from wildfires since records began in 2003.
It follows Spain registering its highest ever wildfire carbon emissions last month.
CAMS said the daily total fire radiative power—a measure of the blazes’ intensity—in France, Spain and Portugal in July and August was “significantly higher” than average.
The service warned that a large proportion of western Europe was now in “extreme fire danger” with some areas of “very extreme fire danger”.
“We have been monitoring an increase in the number and resulting emissions of wildfires as heatwave conditions have exacerbated fires in southwestern France and the Iberian Peninsula,” said Mark Parrington, CAMS senior scientist.
“The very extreme fire danger ratings that have been forecasted for large areas of southern Europe mean that the scale and intensity of any fires can be greatly increased, and this is what we have been observing in our emissions estimates and the impacts it has on local air quality.”
CAMS released satellite imagery showing a plume of smoke from the huge in southwestern France extending hundreds of kilometres over the Atlantic.
France has received help battling the latest blaze—which is 40-kilometres (25 miles) wide and which forced some 10,000 people to evacuate the region—in the form of 361 firefighters from European neighbours including Germany, Poland, Austria and Romania.
Globally, 2022 is currently the fourth highest year in terms of wildfire carbon, CAMS said.
Scientists say heatwaves such as the exceptional hot and dry spell over western Europe are made significantly more likely to occur due to manmade climate change.
Citation:
2022 sets record fire activity in southwest Europe: EU (2022, August 12)
retrieved 12 August 2022
from https://phys.org/news/2022-08-southwest-europe-eu.html
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The fossil was first unearthed in Ethiopia in 1967.
One of the oldest known Homo sapiens fossils may be more than 35,000 years older than previously thought, according to a study on Wednesday that used volcanic ash to date the find.
Kibish Omo I, first unearthed in Ethiopia in 1967, contained only bone and skull fragments which were difficult to date directly and experts long remained divided over their age.
Geologists in 2005 analysed the layer of rock just underneath the find and determined Omo I was at least 195,000 years old.
That made the Homo sapiens fossil at least that old—and the oldest ever discovered at the time.
“But there was still a lot of uncertainty,” Celine Vidal, the main author of the study published in leading scientific journal Nature, told AFP.
Vidal, a volcano expert at the University of Cambridge, said getting a more precise date meant analysing the thick layer of ash deposited above the fossils.
“At the time that was nearly impossible since the ash was so fine, almost like flour,” she said.
But thanks to more refined methods available today Vidal’s team was able to link that layer of ash to a major eruption of a volcano named Shala.
According to the study, the ash revealed the layer where Omo I was found to be 233,000 years old, with a 22,000-year margin of error.
“This is a major jump in time,” said study co-author and paleoanthropologist Aurelien Mounier.
He added that the new minimum age for Omo I is more consistent with the most recent theories of human evolution.
It also brings it closer to the age given to what are today the oldest Homo sapiens remains, discovered in Morocco in 2017 and dated to 300,000 years ago.
The skulls and teeth unearthed in Jebel Irhoud torpedoed the long-held theory that we emerged from an East African “cradle of humankind”.
But for Mounier, the physical characteristics of the Moroccan fossils are a less convincing ancestor of today’s humans than Omo I.
The Jebel Irhoud fossils are described as having a modern face but a brain case that, though large, has a more archaic-looking shape.
“Omo I is the only fossil that has all the morphological characteristics of modern man,” said Mounier.
Citation:
One of the oldest human fossils just got older: study (2022, January 15)
retrieved 16 January 2022
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As the days shorten and temperatures drop in the northern hemisphere, leaves begin to turn. We can enjoy glorious autumnal colours while the leaves are still on the trees and, later, kicking through a red, brown and gold carpet when out walking.
When temperatures rise again in spring, the growing season for trees resumes. Throughout the warmer months, trees take carbon dioxide from the atmosphere and store it in complex molecules, releasing oxygen as a byproduct. This, in a nutshell, is the process of photosynthesis. The more photosynthesis, the more carbon is locked away.
We know that carbon dioxide is a major driver of climate change, so the more that can be taken out of the atmosphere by plants, the better. With the warmer climate leading to a longer growing season, some researchers have suggested that more carbon dioxide would be absorbed by trees and other plants than in previous times. But a new study has turned this theory on its head and could have profound effects on how we adapt to climate change.
Reaching the limit
The researchers, led by Deborah Zani at the Swiss Federal Institute of Technology, studied the degree to which the timing of colour changes in autumn tree leaves was determined by the growth of the plant in the preceding spring and summer.
Temperature and day length were traditionally accepted as the main determinants of when leaves changed colour and fell, leading some scientists to assume that warming temperatures would delay this process until later in the season. Studying deciduous European tree species, including horse chestnut, silver birch and English oak, the authors of the new study recorded how much carbon each tree absorbed per season and how that ultimately affected when the leaves fell.
Using data from the Pan European PhenologyProject, which has tracked some trees for as long as 65 years, the researchers found in their long-term observational study that as the rate of photosynthesis increased, leaves changed colour and fell earlier in the year. For every 10% increase in photosynthetic activity over the spring and summer growing season, trees shed their leaves, on average, eight days earlier.
Climate-controlled experiments on five-year-old European beech and Japanese meadowsweet trees suggest what could be behind this unexpected result. In these trials, the trees were exposed to full sun, half shade or full shade. The results show that there is a limit to the amount of photosynthesis that a tree can carry out over a growing season. Think of it like filling a bucket with water. It can be done slowly or quickly, but once the bucket is full, there is nowhere for any more water to go.
This research shows that deciduous trees can only absorb a set amount of carbon each year and once that limit is reached, no more can be absorbed. At that point, leaves begin to change colour. This limit is set by the availability of nutrients, particularly nitrogen, and the physical structure of the plant itself, particularly the inner vessels which move water and dissolved nutrients around. Nitrogen is a key nutrient which plants need in order to grow, and it’s often the amount of available nitrogen that limits total growth. This is why farmers and gardeners use nitrogen fertilisers, to overcome this limitation.
Together, these constraints mean that carbon uptake during the growing season is a self-regulating mechanism in trees and herbaceous plants. Only so much carbon can be taken up.
Earlier autumn colours
In a world with increasing levels of carbon in the atmosphere, these new findings imply that warmer weather and longer growing seasons will not allow temperate deciduous trees to take up more carbon dioxide. The study’s predictive model suggests that by 2100, when tree growing seasons are expected to be between 22 and 34 days longer, leaves will fall from trees between three and six days earlier than they do now.
This has significant implications for climate change modelling. If we accept that the amount of carbon taken up by deciduous trees in temperature countries like the UK will remain the same each year regardless of the growing season, carbon dioxide levels will rise more quickly than was previously expected. The only way to change this will be to increase the capacity of trees to absorb carbon.
Plants that aren’t limited by the amount of nitrogen available may be able to grow for longer in the warming climate. These are the trees which can take nitrogen from the air, such as alder. But these species will still lose their leaves at roughly the same time as always, thanks to less daylight and colder temperatures.
But on the upside, with the prospect of some trees losing their leaves earlier and others losing them at the time they do now, there might be the prospect of prolonged autumnal colours—and more time for us to kick through the leaves.
More information:
Deborah Zani et al. Increased growing-season productivity drives earlier autumn leaf senescence in temperate trees, Science (2020). DOI: 10.1126/science.abd8911
Citation:
Climate change is making autumn leaves change colour earlier—here’s why (2020, November 27)
retrieved 28 November 2020
from https://phys.org/news/2020-11-climate-autumn-colour-earlierhere.html
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