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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Telangana CM urges Amit Shah to increase sanctioned strength of IPS officers in state
Hyderabad (PTI): Telangana Chief Minister A Revanth Reddy met Union Home Minister Amit Shah in Delhi on Wednesday night and urged him to increase the sanctioned strength of IPS officers to the state in view of its growing administrative and security needs.
The two leaders also discussed the recent surrender of several senior Maoist leaders before the Telangana Police and other issues.
"During the meeting, the two leaders discussed the issue of Maoist surrenders and their rehabilitation. The chief minister informed Shah that significant improvements in policing have taken place in Telangana over the past two years," an official release here said.
Highlighting that 591 Maoists have laid down their arms and joined the mainstream of society during this period, the chief minister said the state government was providing them compensation and rehabilitation assistance as per the rules.
He requested the Union home minister to extend financial support from the central government for development works in the backward regions of the state.
Reddy also urged Shah to increase the sanctioned strength of IPS officers to the state from 83 to 105 in line with the state's growing administrative and security needs, the statement said.
The first cadre review after the formation of Telangana was conducted in 2016, while the next review, due in 2021, was delayed and finally carried out in 2025. Even then, only seven additional IPS officers were allocated to the state, the chief minister informed Shah and requested that the third cadre review be conducted in 2026 as per the schedule.
Reddy explained that Telangana, like the rest of the country, is facing several modern challenges, including cybercrime, drug trafficking, white-collar crimes, and other emerging security threats.
He highlighted the reorganisation of the Hyderabad, Cyberabad, and Malkajgiri Police Commissionerates, the proposed formation of the Future City Commissionerate and the rapidly growing population in Hyderabad to underline the increasing administrative requirements of the state.
