As the economy shrinks, global warming will ease – but it will not disappear, and there is no honest basis for saying when it might.

Economic contraction reduces energy use, transport, construction, manufacturing and long supply chains. These are the main sources of greenhouse gas emissions. If contraction is deep and long-lasting, emissions will fall sharply. On this point there is little dispute. A smaller economy emits less carbon.

But global warming is not driven by today’s emissions alone. It is driven by the accumulation of greenhouse gases already in the atmosphere. Carbon dioxide remains for centuries. Methane is shorter-lived but highly potent. Even if emissions were cut close to zero, temperatures would remain elevated for a very long time. Some further warming would still occur because the climate system responds slowly.

This means there is no moment at which global warming simply stops. There is only a slowing, then possibly a stabilisation, and only much later a very gradual decline.

Some changes are already locked in. Sea levels will continue to rise for centuries. Oceans will stay warmer and more acidic. Ice loss will not reverse on any meaningful human timescale. These processes do not respond quickly to economic change.

What contraction can do is prevent escalation. It can stop warming from running away beyond human capacity to adapt. That is not a full solution, but it is the difference between difficulty and collapse.

Timing matters, and here certainty is not possible. If global economic contraction were sustained:

• emissions could fall within one or two decades
• temperature rise might stabilise later this century
• climate instability would persist for many decades
• sea level rise would continue well beyond 2100

There is no credible date at which the problem “goes away”.

The honest conclusion is this. A shrinking economy does not restore the old climate. It limits further damage and makes adaptation possible. That is not failure. It is realism. It shifts the task from chasing growth-based fixes to learning how to live within new climatic limits, locally and materially.

That is as far as authenticity allows us to go.