Is it too late to reverse climate change?

Is it too late to turn the climate around? I'll check the latest science on reversibility and tipping points.

No — it is not too late to limit climate change, but it is too late to fully reverse it to pre-industrial conditions quickly or easily.

Scientists make a distinction between reversing climate change completely and stopping or limiting further warming:

1. Some change is already locked in and irreversible on human timescales

> Humans have caused major climate changes to happen already, and we have set in motion more changes still.
> if we stopped emitting greenhouse gases today, the rise in global temperatures would begin to flatten within a few years. Temperatures would then plateau but remain well-elevated for many, many centuries.

> While the effects of human activities on Earth's climate to date are irreversible on the timescale of humans alive today, every little bit of avoided future temperature increases results in less warming that would otherwise persist for essentially forever.

The Intergovernmental Panel on Climate Change (IPCC) has said:

> “A large fraction of climate change is largely irreversible on human time scales,”

> 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.

One study's climate policy implication is that:

> climate change cannot be completely reversed even if all the external forces are returned to their initial values.

This is described as:

> Climate change: irreversible but not unstoppable

Reasons for irreversibility:

> Once crossed, these changes cannot be undone on human timescales — ice sheet collapse takes centuries to reverse, permafrost carbon release takes millennia

The report warns of "tipping points" with irreversible and cascading effects, including the loss of the West Antarctic and Greenland ice sheets, the loss of the Amazon rain forest and the shutdown of the Atlantic Ocean circulation system

Other long-lasting legacies:

> “Sea level rise is unavoidable for centuries to millennia due to continuing deep-ocean warming and ice sheet melt,”

2. It is NOT too late to limit how bad it gets — and even partially reverse warming

NASA and the IPCC emphasize a two-tier approach:

> But it may not be too late to avoid or limit some of the worst effects of climate change.
> Responding to climate change will involve a two-tier approach: - “Mitigation” – reducing the flow of greenhouse gases into the atmosphere - “Adaptation” – learning to live with, and adapt to, the climate change that has already been set in motion.

> While we cannot stop global warming overnight, we can slow the rate and limit the amount of global warming by reducing human emissions
> But it may not be too late to avoid or limit some of the worst effects of climate change.

> stabilizing emissions at today’s rates will not stop global warming
> To stop global warming, we will have to significantly reduce not just stabilize, emissions

The IPCC says it is:

> It is not too late to make a difference, but it requires an unprecedented level of cooperation, innovation, and determination

And:

> IPCC: It’s not too late if we take climate action now

Even if we overshoot 1.5°C — which one UN report says:

> it's already too late to keep global warming under the 1.5°C threshold

— scientists note:

> if greenhouse gas emissions drop quickly enough, that warming will only be temporary, and climate disruption could begin to reverse before the end of the century, although some legacies of our greenhouse gas emissions will last a very long time.

3. Why action still matters enormously

> every fraction of a degree of warming matters to limit the dangers of climate change.

> “Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems,”

> There is no “tipping point” for the planet as a whole. ... every bit of warming we avoid will reduce the extremes of climate fluctuation. ... It will never be too late to take action for the climate.

In short:

The key variable is not time itself but future emissions:

> what will our emissions of carbon dioxide and other pollutants be in the years to come?