Is it too late to reverse climate change?

Is it too late to reverse climate change? I'll gather the latest science on what can still be undone and what can't.

No, it is not too late - but climate change cannot be completely reversed quickly, and some impacts are now unavoidable.

What science says about "reversing" climate change

Scientists make a distinction between stopping further warming, limiting worst impacts, and fully reversing climate change to pre-industrial conditions.

•Completely reversing overnight is not possible. "Completely reversing climate change overnight is not possible. However, we can significantly reduce its impacts by lowering greenhouse gas emissions and restoring natural ecosystems."

Research also concludes that "climate change cannot be completely reversed even if all the external forces are returned to their initial values."

•A large fraction is irreversible on human timescales. "A large fraction of climate change is largely irreversible on human time scales," the most recent assessment report from the Intergovernmental Panel on Climate Change (IPCC) warned. Only if human emissions were "strongly negative over a sustained period" — for example, if tree planting and other activities were to sequester far more carbon than humans release—would climate change begin to be reversed.

•That is why even if nations could bring carbon dioxide back to pre-industrial levels, scientists have warned it would take 1,000 years or longer for the climate changes already triggered to be reversed, and "there's no going back" on that timescale.

•Some aspects will continue to change even if temperatures are stabilized. The IPCC 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, because heat already stored in the ocean keeps water expanding and frozen soils keep thawing.

Because of this slow response, new research finds that to truly stop long-term risks, 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, and that stopping those delayed losses therefore requires net-negative emissions, where humanity removes more carbon dioxide from the atmosphere than it releases year after year.

What is still possible

The IPCC's message is that while it is too late to reverse some of the negative impacts, it is not too late to avoid the worst outcomes:

> While it is too late to reverse some of the negative impacts, the report also found that "strong and sustained" reductions of greenhouse gases could lead to temperature stabilization in 20-30 years

In its most recent report, the IPCC issues a stark warning but also a message of hope. Stockholm Resilience Centre director Line Gordon summarized it:

> "It is still possible to halt current climate change trends and secure a liveable future for all, according to the new IPCC report. But the window of opportunity is narrowing quickly; we must act now."

> "The next few years will play a critical role in deciding our future and that of generations to come," according to the IPCC report.

Other assessments emphasize the same:

•There is no single global tipping point for the planet as a whole, and "every bit of warming we avoid will reduce the extremes of climate fluctuation."

•Therefore "It will never be too late to take action for the climate."

What would "reversing" actually require?

1.Rapid and deep cuts to emissions across energy, transport, industry, agriculture and deforestation. This can halt the rise in global temperature.

2.Sustained net-negative emissions - removing far more carbon than we release through natural solutions (forest restoration, soil carbon, wetland protection) and technological carbon dioxide removal (CDR), for decades to centuries.

3.Adaptation to changes already locked in - because some additional warming is inevitable even if we achieve significant greenhouse gas reductions quickly, we should make plans to adapt to coming climate change.

The widely quoted goal is not to return the climate to what it was in 1850 within our lifetimes, but to stop it getting worse and then slowly draw temperatures down over centuries. Action now determines whether we stabilize around 1.5-2°C, with manageable risks, or head toward 3 to 8 degrees Celsius by the end of the century if emissions continue unchecked.

In short: We can't undo past emissions overnight, and some consequences like sea-level rise and ice sheet loss will last for centuries, but we are not past the point where urgent mitigation and carbon removal can prevent far more dangerous, irreversible changes.

Citations (3)

1thebulletin.orgNews and mediaquality 0.82
Climate change: irreversible but not unstoppable
Backs: “Research also concludes that "climate change cannot be completely reversed even if all the external forces are returned to their initial values.". A large fraction is irreversible on human timescales. "A large fraction of climate change is largely irreversible on human time scales," the most recent assessment report…”
2earth.comNews and media
Stopping climate damage may require centuries of carbon removal
Backs: “That is why even if nations could bring carbon dioxide back to pre-industrial levels, scientists have warned it would take 1,000 years or longer for the climate changes already triggered to be reversed, and "there's no going back" on that timescale. Some aspects will continue to change even if temperatures are…”
3stockholmresilience.orgNot yet classified
IPCC: It’s not too late if we take climate action now
Backs: “While it is too late to reverse some of the negative impacts, the report also found that "strong and sustained" reductions of greenhouse gases could lead to temperature stabilization in 20-30 years”