The dire projections come from the state’s Climate Change Assessment, which analyzes the impacts of changing weather patterns on the nation’s most-populous state.
In hot weather, trees “sweat” to cool down by releasing water from their leaves or needles and then replacing it with water from the soil. But during long periods of high temperatures, trees may release more water than they can replace. To strengthen forests against heat stress and other environmental hazards, scientists have suggested adding fungi to the soil.
Soil fungi living on tree roots are called ectomycorrhizal fungi. They help trees absorb water by expanding their root networks, and trees help the fungi by providing them with sugars for energy. This beneficial partnership is known as symbiosis. Scientists at Fujian Agriculture and Forestry University in China tested whether symbiosis with ectomycorrhizal fungi could help the pine trees Pinus massoniana survive warmer temperatures.
For their experiment, the researchers grew pine seedlings with and without ectomycorrhizal fungi in a greenhouse under different temperature conditions. First, they grew fungi called Cenococcum geophilum for 45 days on a gel-like substance called agar. At the same time, they grew the pine seedlings for 30 days, then transferred them into pots with natural soil.
After 15 days in the pots, the researchers spread the gel-like agar containing the fungi over small 1 x 1 centimeter (cm) areas of the pine root tips to introduce the fungi to the seedlings, a process called inoculation. They assumed that the fungal network would expand from the starting area to colonize new root tips as the seedlings grew. The team’s inoculations included 6 different C. geophilum strains and 1 fungi-free control. To simulate heat stress, the researchers replicated each of the 7 inoculations at 25°C (77°F) and 35°C (95°F). They repeated each inoculation condition in 3 pots with 3 seedlings, for a total of 126 seedlings.
After 60 days, the researchers harvested the pine seedlings and used a microscope to count how many of their root tips had fungi. They divided the number of root tips with fungi by the total number of root tips to calculate a colonization rate. They considered seedlings with a colonization rate of 80% or higher to have successfully formed a symbiotic relationship with the fungi. Then, the researchers analyzed seedlings with an 80% colonization rate to investigate their symbiotic partnerships.
The team observed that pine seedlings grown under heat stress at 35°C were 24% to 59% smaller than those grown at 25°C, and their needles were yellow instead of a healthy green. However, the seedlings that formed a symbiotic relationship with the ectomycorrhizal fungi were greener and 80% heavier than the control seedlings.
Investigating the trees further, the team measured 3 chemical compounds related to plant stress, including malondialdehyde (MDA), proline, and nitric oxide. Plants release MDA when damaged, so high MDA levels mean a plant is struggling. In contrast, plants release proline and nitric oxide to repair cells or hold water, so high amounts of these compounds mean a plant is healing.
To measure MDA and proline levels in the pine needles, the researchers mixed them with different acids that change color depending on the sample’s MDA or proline content. To measure nitric oxide, the researchers mixed the needles with a protein that converts the compound into a chemical that changes color. They found that inoculated seedlings at 35°C had about 30% to 40% less MDA, 15% to 30% more proline, and 150% more nitric oxide in their roots than the control seedlings.
Finally, the researchers measured changes in gene activity in the inoculated pine seedlings. They identified active genes by analyzing RNA molecules from the pine seedling roots with a process called RNA sequencing or transcriptomics. They found that inoculating the seedlings with ectomycorrhizal fungi activated more genes related to root strength, water retention, cell defense, and general plant protection than were activated in the control seedlings.
By combining chemical analyses with growth measurements, the team concluded that a symbiotic partnership with the ectomycorrhizal fungi helped the pine seedlings survive heat stress. They demonstrated that through prolonged heat, inoculated seedlings maintained greener needles and lower levels of stress chemicals. They suggested that ectomycorrhizal fungi could be an ecological tool to help trees stay hydrated in a warming world. They recommended that future researchers conduct field trials with inoculated trees to translate these findings into forest management strategies.
In December 2015, 195 countries at the UN Climate Change Conference signed the Paris Agreement, a legally binding international treaty on climate change. The treaty’s overarching goal was to keep the “temperature increase to 1.5 degrees Celsius above pre-industrial levels.”
While unquestionably meant well, the agreement has quickly turned into little more than a footnote as global warming has stormed ahead. Scientists have long warned that we’re on a path to blaze past that foreboding threshold in a matter of years, possibly by 2030.
And now, according to the latest projections, that day is poised to come even sooner. In a new article in the journal Climate and Atmospheric Science, two researchers from the University of Kansas claim that a recent doubling in the rate of global warming means that we could blow past the Paris Agreement threshold as soon as 2028.
The researchers analyzed temperature records through last year and observed a “statistically significant doubling of the global warming rate” between 2011 and 2025, compared to the period between 1971 and 2025.
“Extrapolating this accelerated rate projects a crossing of the 1.5 degrees Celsius threshold by 2028, nearly a decade earlier than previous estimates,” they concluded. “These findings suggest a narrower window remains to limit warming to 1.5 degrees Celsius, underscoring the urgency for rapid and substantial reductions in greenhouse gas emissions.”
Realistically, it’s hard to imagine that we won’t fail to stop the warming in time.
“However, the inertia of existing political, economic, and technological systems3 limits the pace at which such actions can be implemented, narrowing the remaining window for achieving the 1.5 degrees Celsius target,” the researchers concluded in their paper.
The United States, long among the biggest carbon polluters on the planet, has not only officially withdrawn from the Paris Agreement twice during Donald Trump’s terms as president, but his administration has actively reversed environmental laws while giving the fossil fuel industry free rein through deregulation.
It’s a sad state of affairs that the UN Environment Program appears to be painfully aware of. In a new Emissions Gap Report, published today, the body found that “new climate pledges under the Paris Agreement have only slightly lowered global temperature rise over the course of this century.”
“Given the size of the cuts needed, the short time available to deliver them and a challenging political climate, a higher exceedance of 1.5°C will happen, very likely within the next decade,” the report reads.
Worse yet, we have the tools to make substantial cuts to greenhouse emissions — but we’re not using them due to a lack of incentives.
“The required low-carbon technologies to deliver big emission cuts are available,” the report concludes. “Wind and solar energy development is booming, lowering deployment costs.”
“This means the international community can accelerate climate action, should they choose to do so,” it continues. “However, delivering faster cuts requires would require navigating a challenging geopolitical environment, delivering a massive increase in support to developing countries, and redesigning the international financial architecture.”
As global temperature increase shoots past 1.5 degrees Celsius, the vulnerable countries that fought for that Paris Agreement target face a brutal new reality.
Sweltering summer temperatures put last month on par with July 2023 for global warmth, scientists said. More records could be broken in the months ahead.
Sweltering summer temperatures put last month on par with July 2023 for global warmth, scientists said. More records could be broken in the months ahead.
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