World may breach 1.5° C warming threshold soon, some damage irreversible: UN

The latest UN Environment Programme report has warned that the world is moving dangerously close to breaching the 1.5 degrees Celsius global warming threshold, with temperatures likely to temporarily cross it within the next few years.A top UN official said the findings show that even 50 years of technological progress cannot reverse climate change entirely and warned that "things may not return to normal".The report, titled Limiting Overshoot, said crossing the threshold could intensify extreme weather, accelerate ecosystem loss and threaten the survival of small island developing nations through submersion.It called for immediate and sustained cuts in greenhouse gas emissions, while stressing that governments and investors must plan for changes that are permanent and long-term. UNEP India head Balakrishna Pisupati said some climate impacts can still be reversed, while others cannot, and that this distinction matters for every country, community and individual. He said South Asia faces several overlapping pressures."South Asia is challenged by a number of overlapping problems – demographic pressures, income inequality, unequal access to technology, and a just transition. Like many developing countries, South Asia is largely at the receiving end of global warming," Pisupati said. He added that climate impacts do not stop at national borders. "Many of these changes don't respect political boundaries, which is why we have multilateral processes, negotiations, and frameworks like the UN Framework Convention on Climate Change (UNFCCC)," he said.Pisupati said several climate "clocks" are ticking at the same time, each moving at a different pace. These include the heat clock, glacier clock, sea-level clock, ecosystems clock and human clock.Explaining the difference, he said, "Take the heat clock, the moment we reduce warming, we may see an immediate effect. But the glacier clock is different. Even if temperatures fall back to 1.2 or 1.3 degrees Celsius after a hundred years, glaciers won't simply re-form, and ice caps won't return to how they were in the 1800s or 1900s. Glaciers respond to these changes largely independently of other systems."He said the sea-level clock moves faster, and its effects would be impossible to reverse over a decade even if warming is capped at 1.5 degrees Celsius.On ecosystems, he said, biodiversity loss is permanent because extinct species cannot be brought back in natural conditions, even if modern tools such as synthetic biology and biotechnology can recreate some elements of the past.Referring to the human clock, he pointed to farming communities in parts of India where drought and flooding have already forced families to move and change livelihoods, altering lives in ways that decades of recovery may not undo.Pisupati said biodiversity loss poses the greatest risk of permanent damage. "The loss of biodiversity is where we face the greatest risk of permanent damage. We may be able to name a few million plants, animals, microbes, fish, vertebrates and invertebrates, but many millions more remain unidentified, and even among the known ones, we are losing them at an alarming rate," he said.He added that the crisis is global but hits hardest in countries that bear little historical responsibility for climate change and have fewer resources to deal with its consequences.The UNEP report also raises issues of equity and justice, including fair technology transfer, protection against disproportionate impacts, carbon debt obligations, and the principle of Common But Differentiated Responsibilities and Respective Capabilities, or CBDR-RC.The principle says all countries must act on climate change, but developed nations should take primary responsibility because they account for most historical and current greenhouse gas emissions.Asked how these ideas can lead to real progress instead of prolonged negotiations, Pisupati said countries with greater resources and a long history of emissions must take on more responsibility than countries with low per-capita emissions that contribute little but suffer heavily."This is precisely why CBDR has become so important in negotiations, and rightly so, for many countries including India, whose negotiating positions are consistently anchored in it," he said.On carbon debt, he said countries that have historically driven cumulative emissions are expected to help meet the costs of mitigation, adaptation, and loss and damage."Carbon debt is an element that deserves more attention. Countries that have historically emitted and contributed to today's changes, impacts that have built up cumulatively over decades, bear a responsibility to help address some of these problems," he said.He added that countries with the technology, historical responsibility and resources should help bear these costs.Pisupati said the need to turn commitments into action is now more urgent than ever because promises mean little unless they help vulnerable countries survive. "This is no longer just an environmental issue. It is a survival issue, a development issue, a health issue, a social and economic issue," he said.- EndsPublished By: India Today Web Desk Published On: Sep 5, 2026 17:58 IST