Stopping climate damage may require centuries of carbon removal

Reaching net-zero emissions is often described as the moment humanity finally brings climate change under control. But scientists now say the story may not end there.

New research shows that some climate damage keeps building long after temperatures stop rising. Sea levels can continue creeping upward, and frozen northern soils can keep thawing, releasing more carbon into the atmosphere.

To truly stop those long-term risks, researchers say the world may eventually need to remove more carbon dioxide than it emits for centuries, turning net zero into just the first step of a much longer climate strategy.

Climate damage keeps growing

Sea level rise and thawing northern soils continue intensifying long after global temperatures stabilize at about 2.7°F (1.5°C) above preindustrial levels.

Analyzing long-term climate pathways, Johannes Bednar at the International Institute for Applied Systems Analysis (IIASA) documented how those delayed impacts keep growing unless carbon removal continues for centuries.

Even in optimistic scenarios where emissions peak soon and warming eventually declines, both processes keep building for generations.

Stopping their growth therefore depends not only on cutting emissions quickly, but also on sustaining large-scale carbon removal far beyond current climate timelines.

Slow responses drive lasting damage

Rising water and thawing ground do not stop on cue, because ice, oceans, and frozen soils respond slowly to warming.

Heat already stored in the ocean keeps water expanding, while thaw exposes buried organic matter that microbes convert into carbon dioxide and methane.

Because these systems react over decades or centuries, their impacts can continue intensifying long after global temperatures stabilize.

The Intergovernmental Panel on Climate Change has warned that sea level will keep rising beyond 2100 even if warming stays near about 2.7°F (1.5°C) above preindustrial levels.

That slow-motion response means temperature stability alone does not freeze climate risks in place. Stopping those delayed losses therefore requires net-negative emissions, where humanity removes more carbon dioxide from the atmosphere than it releases year after year.

Delays in cutting pollution make that future burden steeper, and the worst-case pathways also produce a wider range of possible damage.

Carbon emissions from permafrost

Thawing permafrost – ground that remains frozen for years – adds another complication by releasing carbon long locked away underground.

Once soils warm and microbes become active, they break down ancient plant matter and release carbon dioxide and methane into the atmosphere.

Bednar’s team estimated that permafrost emissions could add about five percent to total carbon removal needs even in relatively favorable climate pathways.

A second analysis reached similar conclusions while testing climate policy under physical uncertainty from the start. When planners treated dangerous outcomes as risks to avoid, the least-cost strategy shifted toward earlier action and stronger pricing of climate pollution.

In those scenarios, net zero often arrived about a decade sooner, and the cost of carbon pollution roughly doubled.

Acting cautiously changed the economic calculation before damage became unavoidable, rather than waiting for worsening impacts to reveal themselves later.

Carbon removal becomes permanent

In these scenarios, carbon removal did not appear as a temporary patch for missing a temperature target.

Instead, the models continued removing carbon after the hottest years had passed to gradually reduce long-term climate danger.

Planned cooling after the peak became part of risk management itself, not simply a cleanup step after overshooting a goal.

Seen this way, carbon removal becomes permanent climate infrastructure. Maintaining it over centuries raises difficult questions about cost, fairness, and whether political systems can sustain commitments far beyond the time horizons of current governments.

Future cleanup responsibilities

Legal pressure entered the debate on July 23, 2025, when the International Court of Justice issued a climate advisory opinion stating that countries have a duty to prevent significant climate harm.

Researchers pointed to that opinion as support for the idea that preventing delayed climate damage may require obligations that extend far beyond current policy timelines.

A climate promise framed around 2050 alone looks thin if sea levels and other risks continue rising long after those deadlines pass.

Centuries of carbon removal would outlast governments, parliaments, and most institutions that currently shape climate policy.

That is why both papers and an IIASA statement called for durable frameworks that connect today’s emissions decisions with future cleanup responsibilities.

“Delayed impacts are not abstract future risks – they represent significant harm affecting hundreds of millions of people through sea-level rise and infrastructure damage,” said Bednar.

He added that taking the court’s opinion seriously would mean committing to carbon removal efforts that extend far beyond today’s climate targets.

Climate fight goes beyond net zero

The Paris Agreement still matters, but these studies suggest its temperature limits should be viewed as milestones rather than finish lines.

Early emissions cuts can hold peak warming down, while long-term carbon removal determines how far temperatures eventually fall.

That means climate safety may depend not only on stopping pollution, but also on continuing to pull carbon from the atmosphere long after emissions stop rising.

Countries that grow wealthier later this century may therefore face stronger pressure to commit to both faster emissions cuts and dedicated carbon-removal targets.

In this view, reaching net zero is not the end of the challenge. It is only the beginning of a longer effort to stabilize the climate.

The research frames climate safety as a two-part task: reduce pollution rapidly now, then maintain carbon removal for decades – or even centuries – after today’s political cycles have passed.

That approach could reduce long-lived climate risks, but it would also require institutions strong enough to sustain commitments across generations.

The study is published in the journal Environmental Research Letters.

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