The sudden collapse of thawing soils in the Arctic might double the warming from greenhouse gases released from tundra, warn Merritt R. Turetsky and colleagues.
This much is clear: the Arctic is warming fast, and frozen soils are starting to thaw, often for the first time in thousands of years. But how this happens is as murky as the mud that oozes from permafrost when ice melts.
As the temperature of the ground rises above freezing, microorganisms break down organic matter in the soil. Greenhouse gases — including carbon dioxide, methane and nitrous oxide — are released into the atmosphere, accelerating global warming. Soils in the permafrost region hold twice as much carbon as the atmosphere does — almost 1,600 billion tonnes1.
What fraction of that will decompose? Will it be released suddenly, or seep out slowly? We need to find out.
Current models of greenhouse-gas release and climate assume that permafrost thaws gradually from the surface downwards. Deeper layers of organic matter are exposed over decades or even centuries, and some models are beginning to track these slow changes.
But models are ignoring an even more troubling problem. Frozen soil doesn’t just lock up carbon — it physically holds the landscape together. Across the Arctic and Boreal regions, permafrost is collapsing suddenly as pockets of ice within it melt. Instead of a few centimetres of soil thawing each year, several metres of soil can become destabilized within days or weeks. The land can sink and be inundated by swelling lakes and wetlands.
Read More at Nature
Nasa has sent up an instrument to the International Space Station (ISS) to help track carbon dioxide on Earth.
OCO-3, as the observer is called, was launched on a Falcon rocket from Florida in the early hours of Saturday.
The instrument is made from the spare components left over after the assembly of a satellite, OCO-2, which was put in orbit to do the same job in 2014.
The data from two missions should give scientists a clearer idea of how CO2 moves through the atmosphere.
One way this will be achieved is through the different perspectives OCO-2 and OCO-3 will get.
The former flies around the entire globe in what's termed a sun-synchronous polar orbit, which leads to it seeing any given location at the same time of day.
The latter, on the other hand, because it will fly aboard the station, will only see locations up to 51 degrees North and South; and see them at many different times of day.
That's interesting because plants' ability to absorb CO2 varies during the course of daylight hours. OCO-3's dataset will therefore have much to add to that of its predecessor.
"Getting this different time of day information from the orbit of the space station is going to be really valuable," Nasa project scientist Dr Annmarie Eldering told BBC News.
"We have a lot of good arguments about diurnal variability: plants' performance over different times of day; what possibly could we learn? So, I think that's going to be exciting scientifically."
Read more at BBC
Em uma decisão histórica e exemplar para outras nações, o Parlamento do Reino Unido aprovou uma moção ontem (01/05), que declara uma emergência a crise ambiental e das mudanças climáticas pela qual a humanidade passa.
A medida foi uma iniciativa do partido trabalhista e seu líder, Jeremy Corbyn, disse em discurso, que não há mais tempo a perder. “Vivemos em uma crise climática que ficará fora de controle, caso não agirmos de maneira urgente. Não estamos mais falando sobre um futuro distante. Estamos falando de nada menos do que a destruição irreversível do meio ambiente durante nossa atual existência”.
A moção acontece logo após Londres enfrentar os protestos pacíficos realizados pelo movimento Extinction Rebellion, que tomaram conta das principais ruas e centros turísticos da capital inglesa.
Durante as últimas semanas, manifestantes interromperam o tráfego e interditaram várias regiões da cidade pedindo mais ações do governo britânico para enfrentar o aquecimento global.
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