Climate scientists have understood for decades that unchecked, man-made global warming will wreak havoc on human civilization. The challenge has only grown more urgent as the scientific understanding expands and the world begins to feel the impacts.

Now, a landmark U.N. report offers both a glimmer of hope and a giant warning. Scientists and policymakers have the knowhow to address climate change and stave off some of the worst effects of the phenomenon, but political leaders are nowhere close to fully undertaking any of these steps, the report shows.

Scientists on the Nobel Prize-winning Intergovernmental Panel on Climate Change (IPCC) point to a global temperature rise of 1.5°C as a threshold the planet cannot cross without seeing the worst effects of climate change. Yet according to the U.N. organization’s latest report, temperatures have already risen 1°C as a result of human activity, and the planet could pass the 1.5°C threshold as early as 2030 if greenhouse gas emissions continue at the current rate.

“We need a plan to save us,” Mary Robinson, a former U.N. Special Envoy on Climate Change and a previous president of Ireland, tells TIME. “We have a short window of time and a huge responsibility.”

To keep temperatures from rising more than 1.5°C, humans need to shift the trajectory of carbon dioxide emissions so that we either stop emitting by around 2050, or pull more carbon out of the atmosphere than we release. That’s a tall order given the extent to which we rely on fossil fuels to power our vehicles, homes and factories.

As daunting as the task may sound, the IPCC report hints at good news: scientists already have the technical wherewithal to limit temperature rise to the target 1.5°C.

“Limiting warming to 1.5° is not impossible, but will require unprecedented transitions in all aspects of society,” Hoesung Lee, chair of the IPCC, said at a press conference in Seoul Monday. “Every bit of warming matters.”

Among other things, the list of solutions includes energy efficiency, electrifying transport and pulling carbon dioxide out of the atmosphere by reforesting regions and using carbon capture technology. The rapid deployment of renewable energy will also play a key role. To keep temperatures at the target, renewable energy will need to provide at least 70% of global electricity in 2050, while coal use will essentially need to disappear.

Some of these changes are already in motion. Renewable energy sources like wind and solar power have expanded rapidly in recent years largely as a result of market forces. That growth is expected to continue in the coming decades as the price of renewable energy technologies continues to fall.

But the change isn’t coming fast enough. Reaching the target will require government action, including support for research and development, and modification of the way markets work to account for the negative effects of burning fossil fuels.

“The energy transition we need now for climate purposes needs to move much faster,” says Adnan Amin, who heads the International Renewable Energy Agency (IRENA). “We need policy mechanisms.”

The IPCC report is intended to help spur those policies. Negotiators brokering the 2015 Paris Agreement included the 1.5°C marker as an “ideal target” following a push from developing countries that feared their nations may be lost if temperature rise exceeds that level. The IPCC was asked to study the feasibility of the 1.5°C threshold and how it might be achieved.

Read More: World Approves Historic ‘Paris Agreement’ to Address Climate Change

The new report, released Monday in Seoul, shows we are nowhere close, and the government commitments made in 2015 by some 190 countries to reduce their greenhouse gas emissions would still allow temperatures to rise more than 3°C.

It has not helped that in the wake of the historic Paris Agreement, which at the time seemed to herald a new era of cooperation on climate change, many countries have taken a step back from implementing measures to slash emissions. President Donald Trump has promised to withdraw the U.S. from the Paris Agreement entirely, while climate change plans in other countries, including Germany, Australia and Canada, have faced unexpected challenges.

“The world is not achieving the goals under Paris,” California Governor Jerry Brown told TIME last month. “It’s stalled.”

Brown and others have tried to restart those efforts with a series of summits, policy announcements and corporate commitments all designed to put pressure on national governments ahead of the upcoming U.N. climate conference in Poland this December. But with political disruptions across the globe the challenge remains steep.

“The main difference between possibility and impossibility is just political will,” says Chris Weber, WWF‘s global climate and energy lead scientist.

The consequences of failure would be immense and affect countries and their citizens in every corner of the globe. But the most worst toll would be inflicted on developing countries that lack the resources to adapt and communities located in vulnerable regions like coastlines, small islands and particularly dry regions.

“We need a ‘climate just’ pathway,” says Robinson. “The risks posed by global warming in excess of 1.5°C are large and unpredictable and in some cases irreversible.”

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Write to Justin Worland at justin.worland@time.com.