Some tree leaves will fall 3-6 days in advance by end of century due to climate change: Study
Berlin: A large-scale study of European trees suggests that the leaves of trees between the tropics and the polar regions of the Earth will start to fall in advance by three to six days by the end of the 21st century rather than lengthening by one to three weeks as current models have predicted.
The scientists, including those from the University of Munich (LMU) in Germany, said earlier studies had predicted that the shedding of leaves from these temperate trees will get later under the ongoing climate crisis.
They said early observations also supported this idea since warming caused leaves to stay on the trees later over recent decades, driving increased growing season length that could help to slow the rate of climate change.
However, the current study, published in the journal Science, showed that this trend might be reversed as increasing photosynthetic productivity begins to drive earlier autumn leaf fall or senescence.
According to the researchers, the results build on growing evidence that plant growth is limited by the ability of tree tissues to use and store carbon.
While changes in the growing-season lengths of temperate trees greatly affect global carbon balance, they said future growing-season trajectories remain highly uncertain since the environmental drivers of autumn leaf senescence are poorly understood.
Autumn leaf-shedding at the end of the growing season in temperate regions is an adaptation to stressors, such as freezing temperatures, the scientists explained.
While a common assumption is that alleviating a warmer climate could allow leaves to persist longer and consume more atmospheric carbon, the researchers said the role of photosynthesis in governing the timing of leaf senescence has not been widely tested in trees.
In the current study, the scientists used long-term observations from dominant Central European tree species from 1948 to 2015, and experiments designed to modify carbon uptake by trees, to evaluate related impacts on senescence.
"Accounting for this effect improved the accuracy of senescence predictions by 27 to 42 percent and reversed future predictions from a previously expected 2- to 3-week delay over the rest of the century to an advance of three to six days," the scientists wrote in the study.
The data revealed that increased growing-season productivity in spring and summer due to elevated carbon dioxide, temperature, or light levels can lead to earlier -- not later -- leaf senescence.
This is likely because roots and wood cease to use or store leaf-captured carbon at a point, making leaves costly to keep, the study noted.
The model built by the researchers forecasted the possibility of slight advances, no delays, in autumn leaf-dropping dates over the rest of the century.
According to the scientists, the results "substantially lower our expectations of the extent to which longer growing seasons will increase seasonal carbon uptake in forests".
However, they said the universality of this pattern in other forest types remains unknown.
The researchers believe it is important to implement such growing-season length constraints in other models that do not consider these dynamics.
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LoP Ashoka targets CM govt over corruption, says being 'shameless' in public life not forgivable
Bengaluru (PTI): Targeting Chief Minister Siddaramaiah and the Congress government in Karnataka on corruption, BJP leader R Ashoka on Friday said, being foolish was forgivable, but being "shameless" in public life was not.
The Leader of Opposition in the state Assembly claimed that in just 30 months of its tenure, the Congress administration has broken every previous record on corruption-related controversies.
He was responding to Siddaramaiah's post on 'X' on Thursday hitting back at the BJP, stating that Upa Lokayukta Justice Veerappa's claims of "63 per cent corruption" were based on his report in November 2019, when BJP's B S Yediyurappa was the CM.
"But Ashoka, without understanding the Upa Lokayukta's statement properly, has ended up tying the BJP's own bells of sins onto our heads and has effectively shot himself in the foot," the CM had said, as he accused Ashoka of foolishness for trying to twist Veerappa's statement to target the current government.
Responding, Ashoka said, "it is one thing to be called foolish in politics, that can be forgiven."
"But in public life, especially in the Chief Minister's chair, one must never become shameless," Ashoka posted on 'X' on Friday addressing Siddaramaiah.
Noting that the CM himself had admitted on the floor of the Assembly that a Rs 87 crore scam took place in the Valmiki Development Corporation, he said that when a CM acknowledges such a massive irregularity inside the floor of the House, the natural expectation is immediate action and accountability.
"But instead of taking responsibility, you continue in office as if nothing has happened. What should the people of Karnataka call this, if not sheer shamelessness," he asked.
Pointing out that the CM's Economic Advisor and senior Congress MLA Basavaraja Rayareddy had publicly stated that under Congress rule, Karnataka has become No.1 in corruption, Ashoka said, "Yet, you still cling to the Chief Minister's chair without a moment of introspection. What should the people of Karnataka call this, if not sheer shamelessness."
Senior Congress MLA C R Patil had exposed the "money for House" racket in the Housing Department and even warned that the government would collapse if the details he has were made public, Ashoka said.
"Despite such serious allegations from within your own party (Congress), you neither initiated an inquiry nor acted against the concerned minister. What should the people of Karnataka call this, if not sheer shamelessness," Ashoka asked the CM.
Highlighting the "40 percent commission" allegation Congress made against the previous BJP government, the opposition leader said, the commission that the Siddaramaiah government appointed concluded that the accusation was baseless.
"After your own panel demolished your own claim, what moral right do you have to continue repeating that allegation. What should the people of Karnataka call this, if not sheer shamelessness," he asked.
For the last two and a half years, Karnataka has been 'drowning' in corruption, scandals, irregularities and allegations across departments. Ashoka said, "If I begin listing every case that emerged under your government, even 24 hours would not be enough."
"And the most tragic aspect of your administration is this: the unbearable pressure, corruption demands and administrative harassment under your government pushed several officers and contractors into extreme distress - including the suicide of Chandrasekharan which exposed the Valmiki Development Corporation scam - a sign of how deeply broken the system has become under your watch," he said.
Instead of fixing this hopeless environment, the government has tried to bury every complaint and silence every voice, he charged.
"Being foolish is forgivable, but being shameless in public life is definitely not."
"When your own ministers admit scams, when your own advisors certify Karnataka as No.1 in corruption, and when your own MLAs expose rackets inside your departments - clinging to power without accountability is not leadership. It is shamelessness in its purest form." PTI KSU
Earlier on Thursday Ashoka had demanded that the corruption case and allegations in the state against the Congress government be handed over to a CBI investigation, citing a reported statement by Upalokaykta Justice Veerappa alleging "63 per cent corruption", following which Siddaramaiah hit back at the BJP leader.
