“The 1.5 degrees Celsius limit is dead,” says climate scientist

A new study published by legendary climate scientist James Hansen and a global team of researchers Thursday indicates that climate change is accelerating and the world is likely to surpass the 1.5 degrees Celsius warming threshold this decade. Scientists believe that this conclusion could sound the alarm in the climate negotiations at the upcoming Climate Summit (COP28), set to begin at the end of this month in Dubai.

In the 2015 Paris Agreement, countries committed to limiting global warming to 1.5 degrees Celsius about average pre-industrial temperatures. However, a new article that a team of scientists, including those from the US space agency United States (NASA) and Columbia University, prepared, presents data suggesting that this objective is already out of reach.

The United Nations Intergovernmental Panel on Climate Change (IPCC) predicts that most emissions scenarios will cause the planet to exceed 1.5 degrees Celsius during the 2020s. A new study led by James Hansen estimates we'll hit the 1.5 degrees Celsius target earlier than predicted.

The big mistake of our scientific community is not making it clear to political leaders what the situation is.

James Hansen, scientist

"Study co-author James Hansen, from Columbia University's Earth Institute, who was one of the first scientists to alert the world in the 1980s to the impact of greenhouse gases in global warming, said, "The 1.5 degrees Celsius limit is dead and buried."

"James Hansen added that the big mistake of our scientific community is that they do not make it clear to political leaders what the situation is."

We are already at 1.2 degrees Celsius

The planet has already experienced a temperature increase of nearly 1.2 degrees Celsius compared to pre-industrial levels. This recent study has sparked a variety of responses from climate scientists. Some, like Michael Mann from the University of Pennsylvania, have expressed skepticism about the findings, stating in a blog post that these conclusions are significantly divergent from mainstream views.

They released this report in the wake of several months of extreme worldwide weather events, including heatwaves in China and severe floods in Libya. Projections indicate that 2023 will be the warmest year ever recorded.

The Climate Summit, scheduled from November 30th to December 12th in Dubai, will gather representatives from various nations to deliberate on the global political measures necessary to regulate greenhouse gas emissions.

Scientists expect the planet to surpass the warming threshold of 1.5 degrees Celsius within this decade. Climatologist James Hansen co-authored a controversial scientific study which came to this conclusion.

Underestimating Earth's sensitivity

The study, published in the Oxford Open Climate Change scientific journal, draws its conclusions from two main factors. The first pertains to the Earth’s sensitivity to greenhouse gases. It suggests that scientists have previously underestimated the impact of rising carbon dioxide levels on the planet’s climate.

The Intergovernmental Panel on Climate Change (IPCC) has roughly estimated that a doubling of atmospheric carbon dioxide levels would result in a global warming of about 3 degrees Celsius. However, a more comprehensive understanding of ancient climate data, derived from sources like ice cores and tree rings, has led to a higher estimate of around 4.8 degrees Celsius, according to the study.

To date, atmospheric carbon dioxide concentrations have increased from approximately 280 parts per million (ppm) in pre-industrial times to about 418 ppm today.

The second factor highlighted in the report is China’s advancements in combating air pollution, primarily caused by sulfur dioxide emissions from coal-fired power plants, along with global efforts to reduce these emissions from maritime transport. While cleaning the skies provides health benefits and saves lives, it also accelerates climate change as aerosols disperse and reflect solar radiation.

Michael Mann of Pennsylvania disputed the notion that the models underestimated climate sensitivity and the impact of declining sulfur dioxide emissions from shipping. However, other experts believe the study aligns with recent investigations. Klaus Hubacek, a climatologist at the University of Groningen in the Netherlands, stated, “Everything is accelerating.”

Earlier this week, a study in the journal Nature Climate Change suggested that to have a 50% chance of limiting warming to 1.5 degrees Celsius, the world would need to achieve net-zero emissions by 2034, significantly ahead of the 2050 global target.

UN report on 1.5 degrees Celsius

A recent report by the United Nations reveals that global governments plan to produce nearly 110% more fossil fuels by 2030 than the maximum limit set to keep global warming within 1.5 degrees Celsius. This is 69% more than the limit for a two-degree Celsius increase.

Despite 151 national governments pledging to achieve net-zero emissions, and forecasts indicating a peak in global coal, oil, and gas demand this decade, government plans are set to increase global coal production through 2030 and global oil and gas production until at least 2050.

Key findings of the report

• Countries should aim to phase out coal production and use almost entirely by 2040, and reduce oil and gas production and use by at least three-fourths from 2020 levels by 2050, considering the risks and uncertainties of carbon capture, storage, and carbon dioxide removal.
• 17 out of 20 countries have pledged to achieve net-zero emissions and many have launched initiatives to cut emissions from fossil fuel production activities. However, none have committed to reducing coal, oil, and gas production in line with limiting global warming to 1.5 degrees Celsius.
• Governments with greater capacity to transition away from fossil fuels should set more ambitious emissions reduction targets and support transition processes in resource-limited countries.

The ‘Production Gap Report’ prepared by the Stockholm Environment Institute (SEI), Climate Analytics, E3G, the International Institute for Sustainable Development (IISD), and the UN Environment Program (UNEP) estimates the government’s planned and estimated production of coal, oil, and gas at a global level.

The report reveals that the US, China, and Iran are the main contributors to the global loss of groundwater storage, with some areas experiencing land subsidence of more than five cm per year. In arid regions like California and Arizona, massive land subsidence is seen due to reliance on groundwater for irrigation. Urban groundwater use in places like Mexico City also causes significant landslides.

The research predicts high subsidence rates in both irrigated and urban areas of Afghanistan, Uzbekistan, Azerbaijan, and Syria, where no previous data has documented the effects of groundwater withdrawal. However, the study predicts subsidence rates in much of Europe to be less than 1 cm per year.

Fossil fuels and role of producers in facilitating

Michael Lazarus, director of the SEI US Center and co-author of the report, stated that COP28 could be a pivotal moment where governments finally commit to phasing out all fossil fuels and acknowledge the role of producers in facilitating a managed and equitable transition from fossil fuel production. He emphasized that governments with the greatest capacity to transition must bear the greatest responsibility for doing so, while also providing financial and other assistance to help other countries do the same.

The report was a collaborative effort, with over 80 researchers from more than 30 countries contributing to the analysis and review. Numerous universities, think tanks, and other research organizations were also involved in this work.

Neil Grant, a climate and energy analyst at Climate Analytics, criticized governments for planning to invest more in a “dirty, dying industry” despite their climate promises, when there are endless opportunities in a thriving clean energy sector. He described the situation as an “economic frenzy” and a “self-created climate disaster.”

Angela Piccheriello, a Senior Researcher at IISD, pointed out the growing gap between government rhetoric and actions, which not only undermines their authority but also increases risks for everyone. She urged governments to increase transparency on how they will achieve emissions reduction targets and introduce legally binding measures to support these targets ahead of COP28.

Katrin Pettersson, a Senior Policy Advisor at e3G, highlighted that demand for coal, oil, and gas is set to peak this decade even without additional policies. She warned that continuing to invest in new fossil fuel production despite declining global demand is a near-term economic gamble. She called on governments to take control of the clean energy transition and align their policies with what is needed for a climate-safe world.

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