Australian tropical rainforest #trees switch in world first from #carbon sink to #emissions source
Researchers say carbon emissions change in #Queensland tropical rainforests may have global climate implications
Australian tropical rainforest trees have become the first in the world to switch from being a #CarbonSink to an #emissions source due to increasingly extreme #temperatures and drier conditions.
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The change, which applies to the trees’ trunks and branches but not the roots system, began about 25 years ago, according to new research published in Nature.
Trees store #carbon as they grow and release it when they decay and die. Overall, #TropicalForests are thought to be #CarbonSinks – absorbing more #CO2 than they release – and uptake is assumed to increase amid rising atmospheric concentration.
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But nearly 50 years of data collected from tropical forests across #Queensland has revealed this crucial #CarbonSink could be under threat.
About 25 years ago, tree trunks and branches in those #forests became a net emitter, with more #trees dying and insufficient new growth, according to the research.
“It’s the first #TropicalForest of its kind to show this symptom of change,” said lead author Dr #HannahCarle from Western Sydney University.
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“We know that the moist tropics in #Australia occupy a bit of a warmer,drier #climate space than tropical forests on other continents, and therefore it might serve as a future analog for what tropical #forests will experience in other parts of the world.”
#ProfAdrienneNicotra from the Australian National University,a co-author of the study, said it remained to be seen whether Australia’s tropical forests were a harbinger for other tropical forests globally and further research was needed.
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But if so, the findings could have significant implications for global #ClimateModels, carbon budgets and climate policies.
“This paper is the first time that this #TippingPoint of a switch from a #CarbonSink to a carbon source in tropical rainforests has been identified clearly – not just for one year but for 20 years,” said #ProfDavidKaroly , an emeritus professor at the #UniversityOfMelbourne and an expert in #ClimateChange science.
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Even though the balance between gains and losses had shifted, these #forests were still playing an important role in soaking up #CO2, #Karoly said. But their reduced capacity to absorb extra #carbon would make #emissions cuts “a lot harder” and require an even more rapid transition away from #FossilFuels.
The analysis drew on a unique set of #ForestData dating back to 1971, including records tracking roughly 11,000 #trees across 20 forest sites in #Queensland.
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It considered the #carbon stored above ground in tree trunks and branches but not the gains and losses below ground from #soil and #roots.
#DrRaphaelTrouve, who studies forest dynamics at the #UniversityOfMelbourne and was not involved in the study, said the research highlighted the value of collecting and maintaining long term data.
Trouve’s own research published earlier this year, which found #MountainAshForests were thinning rapidly under drier and hotter conditions,
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@anna_lillith so the key is to start cutting them down and using them for housing material where they can keep the carbon sequestered!
