World Will Pass 1.5°C Warming Target This Decade, Some Climate Scientists Announce

According to new research published Thursday, the world will soon pass the 1.5°C target that was set to limit the worst impacts of climate change.

The 2015 Paris Agreement set a goal to limit global warming to at most 2°C above pre-industrial levels. But after the agreement went into effect in 2016, more experts expressed the need to keep the limit to 1.5°C, which was also referenced in the accord.

Ahead of the 2023 United Nations Climate Change Conference (COP28) taking place this month, scientists from Columbia University, NASA, and other institutions around the world have published research warning that with the current rate greenhouse gas emissions and existing policies and actions, global warming will pass the 1.5°C target before 2030, and warming will reach 2°C before 2050.

“The 1.5°C limit is deader than a doornail,” James Hansen, study co-author and director of climate science, awareness and solutions at Columbia University’s Earth Institute, said in a press conference. “The 2-degree limit is also dead, unless we take purposeful actions to reduce Earth’s energy imbalance.”

Hansen became a leading climate scientist in the 1980s, when we was among the first scientists to warn about greenhouse gases and their climate impacts during a Senate hearing on the greenhouse effect, E&E News reported.

Now, Hansen joins several other scientists from around the world in publishing research on climate sensitivity. In their study, published in the journal Oxford Open Climate Change, they found time is running out to limit warming and prevent the worst impacts of climate change.

Global warming has already reached 1.2°C above pre-industrial levels, as Reuters reported.

According to the study, scientists have previously underestimated how carbon dioxide concentration would impact climate sensitivity, which can be challenging to track because of feedback loops. Further, the authors noted that while reducing human-made aerosol pollution since 2010 improves air quality and is good for human health, the aerosol particles reflect solar radiation and were creating a cooling effect.

“We’ve made a Faustian bargain here,” Hansen said in a statement. “And the first Faustian payment is now due, because the reduction in aerosols is accelerating global warming.”

The study findings have been controversial. Michael Mann, a climate scientist at the University of Pennsylvania, said in a blog post that the figures in the study are “very much out of the mainstream,” noting that “the standard is high when you’re challenging the prevailing scientific understanding.”

Bärbel Hönisch, a paleoclimatologist and professor at Columbia University, also raised concerns over the findings. “I’d be a little more reserved, but they may well be correct — it’s a nicely written paper,” Hönisch told The Guardian. “It raises a lot of questions that will trigger a lot of research that will bring our understanding forward.”

The study recommends three rapid, required actions the world needs to take to limit emissions and warming. These actions include increasing the costs of greenhouse gas emissions while making clean energy more accessible and widespread; cooperating between countries; and reducing and reversing an energy imbalance on Earth.

“This decade may be our last chance to develop the knowledge, technical capability, and political will for actions needed to save global coastal regions from long-term inundation,” the study authors concluded.