The world’s top body of climate scientists said Monday that unless greenhouse gas emissions decline faster than governments have agreed, temperatures on Earth would fly through a major danger point, warning of the costs of inactivity but also citing optimistic signs of progress.

The study by the Intergovernmental Panel on Climate Change, according to UN Secretary-General Antonio Guterres, highlighted “a litany of unfulfilled climate commitments” by governments and companies, accusing them of fanning global warming by clinging to hazardous fossil fuels.

“It’s a shame file,” he remarked, “cataloguing the hollow commitments that have set us firmly on the path to an unlivable planet.”

In 2015, governments committed to keep global warming well below 2 degrees Celsius (3.6 degrees Fahrenheit) this century, ideally no more than 1.5 degrees Celsius (2.7 Fahrenheit). Yet, since pre-industrial times, temperatures have risen by over 1.1 degrees Celsius (2 degrees Fahrenheit), causing measurable increases in disasters such as flash floods, extreme heat, more intense hurricanes, and longer-burning wildfires, putting human lives in danger and costing governments hundreds of billions of dollars to combat.

“Projected worldwide emissions from (country commitments) put limiting global warming to 1.5 degrees Celsius out of reach and make reducing warming to 2 degrees Celsius more difficult beyond 2030,” the panel stated.

In other words, according to James Skea of Imperial College London, the report’s co-chair, “If we keep acting as we are now, we won’t even be able to restrict warming to 2 degrees, let alone 1.5 degrees.”

The analysis concluded that ongoing investments in fossil fuel infrastructure and the clearance of significant areas of forest for agriculture undercut the substantial emissions reductions required to fulfill the Paris objective.

According to Skea, emissions in 2019 were roughly 12% more than in 2010 and 54 percent higher than in 1990.

Between 2010 and 2019, the pace of growth fell from 2.1 percent per year in the early part of this century to 1.3 percent per year, according to the report’s authors. However, they expressed “high confidence” that unless countries ramp up efforts to reduce greenhouse gas emissions, the world will be 2.4 to 3.5 degrees Celsius (4.3 to 6.3 degrees Fahrenheit) warmer by the end of the century, a level that experts predict will have severe consequences for much of the world’s population.

“To keep global warming below 1.5 degrees Celsius, global greenhouse gas emissions must peak by 2025 at the latest and be cut by 43% by 2030,” he stated.

The group agreed that such reduction would be difficult to accomplish without dramatic, economy-wide changes. It’s more likely that the world’s temperature would rise over 1.5 degrees Celsius, necessitating steps to reduce temperatures, including removing massive amounts of carbon dioxide — the principal greenhouse gas — from the sky.

Many experts believe that this is impossible to do with existing technologies, and that even if it could, it would be significantly more expensive than avoiding emissions in the first place.

Individual nations are not singled out for criticism in the study, which spans hundreds of pages. However, the numbers demonstrate that affluent nations were the first to burn coal, oil, and gas during the industrial revolution, releasing much of the carbon dioxide already in the atmosphere.

According to the United Nations panel, Europe and North America accounted for 40% of emissions since then. East Asia, which includes China, accounts for little over 12% of the total. However, in the mid-2000s, China surpassed the United States as the world’s leading emitter of greenhouse gases.

According to Guterres, several nations and businesses have exploited recent climate talks to create rosy views of their emissions-cutting efforts while continuing to invest in fossil fuels and other polluting industries.

“Some politicians and corporate leaders say one thing and do another,” he remarked. “To put it bluntly, they’re lying. And the consequences will be disastrous.”

However, there is reason to be optimistic in the study.

Its authors discuss a variety of options for getting the globe back on track to 2°C, or even, with much work, back to 1.5°C if that threshold has been crossed. This might need steps like removing CO2 from the atmosphere through natural or artificial ways, as well as potentially dangerous technologies like blasting aerosols into the sky to deflect sunlight.

A rapid shift away from fossil fuels toward renewable energy, such as increasingly cheap solar and wind power, electrification of transportation, reduced meat consumption, more efficient resource use, and massive financial support for poor countries unable to pay for such measures without assistance are among the solutions recommended.

It’s as if mankind has “gone to the doctor in a very ill condition,” with the doctor telling them, “You need to change, and it’s a dramatic transformation.” “If you don’t,” said Pete Smith, a professor of soils and global change at the University of Aberdeen, “you’re in danger.”

“It’s not like going on a diet,” Smith explained. “It’s a whole lifestyle shift.” It’s about adjusting your diet, how much you consume, and adopting a more active lifestyle.”

Plugging methane leaks from mines, wells, and landfills, which emit the strong but short-lived greenhouse gas into the atmosphere, is one step that scientists sometimes refer to as “low-hanging fruit.” Last year’s United Nations climate summit in Glasgow resulted in a deal between the US and China that promises to achieve precisely that.

“The major message we’ve gotten is that human actions put us into this predicament, and human agency can really get us out of it again,” said Skea, co-chair of the panel.

Since the first report in 1990, the panel’s findings have been increasingly frank, and the most recent one, according to Skea, may be the last before the earth reaches 1.5 degrees Celsius of warming.

Last August, it declared human-caused climate change to be “an established reality” and warned that some of the consequences of global warming are now unavoidable. The group released a study in late February that described how rising temperatures could raise the danger of floods, storms, drought, and heat waves throughout the world.

Nonetheless, former British government top science adviser David King, who was not involved in the report’s development, believes the report’s estimates about how much CO2 the world can afford to release are overly optimistic.

“We don’t have a carbon budget left to burn,” said King, who is now the chair of the Climate Crisis Advisory Group.

“It’s exactly the opposite. “We’ve already done too much in terms of putting greenhouse gases up there,” he added, claiming that the IPCC’s calculations ignore new hazards and possibly self-reinforcing impacts such as higher heat absorption into the seas due to sea ice loss and the release of methane as permafrost melts.

U.N. Secretary-General Antonio Guterres repeated such fears, noting experts’ predictions that the globe is “dangerously close to tipping points that might lead to cascading and irreversible climatic effects.”

“However, high-emitting governments and companies aren’t just turning a blind eye; they’re throwing gasoline to the fire,” he added, asking for a halt to new coal, oil, and gas production. “It’s both ethically and economically insane to invest in new fossil fuel infrastructure.”

Vulnerable countries said the research demonstrated that large polluters need to speed up their efforts before the next United Nations climate meeting, which will be held in Egypt this September.

“We’re appealing on the G-20, the world’s greatest polluters, to announce aggressive commitments ahead of COP27, and to achieve those targets — by investing in renewables and eliminating coal and fossil fuel subsidies,” said Tina Stege, the Marshall Islands’ climate ambassador. “It’s past time to follow through on commitments made.”