Global Warming of 1.6C Now Best Case Scenario, New Research Shows

“Limiting peak temperature to below 1.5C is not possible with even moderate likelihood anymore,” said Christoph Bertram, lead author of the new study.

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The world will soon witness an overshoot of the 1.5C global warming target, according to a new study that argues that constraints in implementing climate policies in some countries make the Paris goal no longer feasible.

“Limiting peak temperature to below 1.5C is not possible with even moderate likelihood anymore,” said lead author of the study Christoph Bertram, who is associate research professor at the University of Maryland and guest researcher at the Potsdam Institute for Climate Impact Research (PIK).

Bertram and his colleagues examined dozens of potential scenarios that take into account technological advancements as well as the feasibility of enforcing climate policies in different regions of the world. They found that green tech’s significant contribution in speeding up the energy transition worldwide gives the world a 50% chance of limiting global warming below 1.6C – now the best case scenario.

However, constraints that prevent some governments from implementing climate policies such as a carbon tax reduce the likelihood of staying within this limit to 5-45%. Constraints range from a lack of adequate infrastructure to ineffective bureaucratic systems and are particularly an issue in developing countries, which lack financial resources.

More on the topic: What Obstacles Do Developing Countries Face When Investing in Low-Carbon Energy Projects?

“The world needs to be prepared for the possibility of an overshoot of the 1.5 °C limit by at least one and probably multiple tenths of a degree even under the highest possible ambition,” the study read.

The 1.5C threshold was set in 2015 as part of the Paris Agreement, which established a framework for limiting global warming to below 1.5C or “well below 2C” above pre-industrial levels by the end of the century.

The global average surface temperatures was higher than 1.5C for a full year between July 2023 and June 2024, scientists confirmed in June, which was the hottest June in documented history and the thirteenth consecutive month to break a temperature record.  

While this does not signal a permanent breach of the critical limit, which scientists say is measured over decades, it sends a clear warning to humanity that we are approaching the point of no return much faster than expected. Indeed, scientists warn that breaching the threshold for a prolonged period could trigger multiple tipping points, with devastating and often irreversible consequences affecting the planet’s life-support systems that all societies depend on.

A study published in Nature Communications earlier this month found that every additional 0.1C degree of warming past the critical 1.5C threshold would increase the risk of triggering crucial tipping events between now and 2300.

Tipping points refer to multiple stable states of different planet’s life-support systems that all societies depend on and that, if pushed too far, could result in unstoppable, permanent, and irreversible changes in their state. For instance, continuous external pressure on a system like the Amazon rainforest, the world’s largest and richest biological reservoir and one of the most important natural carbon storage systems, can turn the forest into a savannah and a source of carbon dioxide.

“We are rapidly approaching tipping points, and every 0.1C of avoided warming reduces risk,” said renowned Earth Scientist Johan Rockström, who was part of the research team behind the study. Five tipping elements – including the collapse of the West Antarctic ice sheet and abrupt permafrost thaw – are already within reach.

A recent survey conducted by the Guardian revealed that the 1.5C goal is increasingly out of reach, with nearly half of all lead authors and review editors of the Intergovernmental Panel on Climate Change (IPCC) reports since 2018 saying they believe humanity will breach the threshold. Of the 380 authors and editors interviewed by the Guardian, 132 (34.7%) expect global temperatures to rise by 2.5C this century, while 100 (26.3%) predict at least 3C of warming.

Among the scientists participating in the survey was Ruth Cerezo-Mota, an expert in climate modelling at the National Autonomous University of Mexico who said a 3C scenario is a “hopeful and conservative” estimate. “There is not any clear sign from any government that we are actually going to stay under 1.5C,” she told the Guardian.

Featured image: Wikimedia Commons.