Arctic plants may not provide predicted carbon sequestration potential

Arctic plants may not provide predicted carbon sequestration potential

SOURCE: University of Stirling DATE: July 2, 2020 SNIP: The environmental benefits of taller, shrubbier tundra plants in the Arctic may be overstated, according to new research involving the University of Stirling. Current ecosystem and climate models suggest that, as the Arctic warms, tundra ecosystems are becoming more productive, with greater photosynthesis resulting in more carbon being removed, or sequestered, from the atmosphere. However, most models do not consider the transfer and fate of this carbon below-ground, and how this can interact with soil carbon through the activities of soil microorganisms. This is critically important because the vast majority of carbon in Arctic ecosystems is found in soil and ‘permafrost’ (permanently frozen soil or sediment) in the form of organic matter produced by the incomplete decay of dead plants, animals and soil organisms in cold conditions. The new research considered the impact of a shrubbier Arctic on soil carbon stocks and the overall carbon sequestration potential of these ecosystems. Significantly, it found that some tall shrub communities stimulate recycling of carbon in soils, releasing it back into the atmosphere as carbon dioxide – meaning that more productive shrubs might not always result in greater carbon sequestration. Professor Wookey said: “While previous studies suggest that a warmer, greener Arctic may increase the rate that carbon dioxide is removed from the atmosphere, our research identified an acceleration in the rate of loss of carbon from soils, back into the atmosphere. “This may more than offset carbon sequestration and would, unexpectedly, turn these ecosystems into a net source of carbon dioxide to the atmosphere. Significantly, current ecosystem and climate models do not...
Climate emissions from tropical forest damage ‘underestimated by a factor of six’

Climate emissions from tropical forest damage ‘underestimated by a factor of six’

SOURCE: The Guardian and Science Advances DATE: October 30, 2019 SNIP: Greenhouse gas emissions caused by damage to tropical rainforests around the world are being underestimated by a factor of six, according to a new study. Research led by the University of Queensland finds the climate impact of selective logging, outright clearing and fire in tropical rainforests between 2000 and 2013 was underestimated by 6.53bn tonnes of CO2. The numbers are likely conservative, and also did not include emissions from other woodlands or the massive boreal forests in the high latitudes of the northern hemisphere. Study co-author professor James Watson of the University of Queensland and the Wildlife Conservation Society said: “We have been treating forests as pretty one-dimensional, but we know degradation impacts carbon. The bottom line is that we knew the numbers would be big, but we were shocked at just how big.” Watson said the numbers used for tropical rainforests were “conservative”, adding, “this is a carbon time bomb and policymakers have to get to grips with this”. When countries declare greenhouse gas emissions from changes in forests, they do not account for the CO2 that forests would have continued to soak up for decades had they not been cleared or damaged. This is a measure known as “forgone removal”. The study, published in the journal Science Advances, also accounted for those emissions up to the year 2050 – a timeframe relevant to the global Paris climate change agreement. The study found 6.53bn tonnes of CO2 for foregone emissions and the impacts of other damage that wasn’t being counted. Journal article abstract: Intact tropical forests, free...
Tropical forests used to protect us from climate change. Now, scientists say, they’re making it worse

Tropical forests used to protect us from climate change. Now, scientists say, they’re making it worse

SOURCE: Washington Post and The Guardian DATE: September 28, 2017 SNIP: A surprising scientific study released Thursday presents troubling news about the enormous forests of the planet’s tropical midsection — suggesting that they are releasing hundreds of millions of tons of carbon to the atmosphere, rather than storing it in the trunks of trees and other vegetation. “The losses due to deforestation and degradation are actually emitting more CO2 to the atmosphere, compared with how much the existing forest is able to absorb,” said Alessandro Baccini, the lead author of the study and a researcher at the Woods Hole Research Center. Specifically, the study found that tropical forests are losing 425 million tons of carbon annually, on average, which is the net result after you sum up 861 million tons of losses and 436 million tons of gains as forests grow each year. “Forests are losing more carbon than we thought,” Baccini said. “And one reason they’re losing so much carbon is because there is actually a lot of disturbance in the forest. You don’t have to wait for deforestation. You don’t have to only look for places that completely lost the trees.” This is a far greater loss than previously thought and carries extra force because the data emerges from the most detailed examination of the topic ever undertaken. The authors say their findings – published in the journal Science on Thursday – should galvanise policymakers to take remedial...
More dire data, less climate change concern?

More dire data, less climate change concern?

SOURCE: Deutsche Welle DATE: Dec 10, 2016 SNIP: With Trump poised to dismantle US climate action, is this a sign of public burnout on the climate topic? Although European voters have indicated they see climate change as a more important factor in their voting than Americans, a similar trend is present: less importance attached to the climate change issue in the face of more short-term fears – such as terrorism, immigration and perhaps imminent geopolitical conflict. But even as climate change recedes from the spotlight, recent evidence shows that the situation is perhaps even more dire than originally thought: Two alarming new studies released over the past month have scientists worried. This week, the Colorado-based National Snow and Ice Data Center revealed that both the Arctic and Antarctic experienced record lows in sea ice extent in November – astonishing scientists who say it is unprecedented for sea ice to retreat at a time when the Arctic enters the coldest, darkest part of the year. The news has policymakers worried as well. “This news from the Arctic might be the start of a tipping point that we must avoid, because this would mean that we as human beings are losing control,” said Gerben-Jan Gerbrandy, a Dutch Liberal member of the European Parliament, at an event this week. … Last week, the Yale School of Forestry and Environmental Studies revealed alarming new research showing that the long-theorized “feedback loop” of climate change and soil carbon loss is indeed a real phenomenon – meaning that the rate of global temperature could rise much faster than expected. Thomas Crowther, who conducted the research,...
Temperatures Could Rise Far More Than Previously Thought If Fossil Fuel Reserves Burned

Temperatures Could Rise Far More Than Previously Thought If Fossil Fuel Reserves Burned

SOURCE: DeSmog Canada and Nature Climate Change DATE: May 23, 2016 SNIP: These models simulate, in response to 5 EgC of CO2 emissions, global mean warming of 6.4–9.5 °C, mean Arctic warming of 14.7–19.5 °C, and mean regional precipitation increases by more than a factor of four. These results indicate that the unregulated exploitation of the fossil fuel resource could ultimately result in considerably more profound climate changes than previously suggested. — Nature Climate Change Imagine a world where average temperatures are almost 10 degrees Celsius higher than today, an Arctic with temperatures almost 20 degrees warmer and some regions deluged with four times more rain. That is the dramatic scenario predicted by a team of climate scientists led by the University of Victoria’s Katarzyna Tokarska, who looked at what would happen if the Earth’s remaining untapped fossil fuel reserves are burned. Tokarska, a PhD student at UVic’s School of Earth and Ocean Sciences, used simulations from climate models looking at the relationship between carbon emissions and warming — including the Intergovernmental Panel on Climate Change report — and concluded that known fossil fuel reserves would emit the equivalent of five trillion tonnes of carbon emissions if burned. That would result in average global temperature increases between 6.4 degrees and 9.5 degrees Celsius, with Arctic temperatures warming between 14.7 degrees and 19.5 degrees, says the paper published Monday in the scientific journal Nature Climate Change. — DeSmog...