My understanding of climate change is that a large increase in human-caused CO2 emissions is likely to lead to large change in the Earth's climate through a global warming effect. Scientific consensus appears to me to be that if we make similarly large reductions in CO2 emissions, we can reduce the magnitude of the consequent warming.

I also understand the climate to have many non-linear mechanisms whereby the link between emission and warming isn't at all straightforward - and so we can only talk about broad averages and so forth, rather than make specific weather predictions.

So is it always true that a reduction in emissions will - on average - cause a reduction in the global warming effect, however small? Or does the existence of tipping points or any other factor mean that only large reductions can make a difference now and any lesser reduction will be pointless?

My intuition says that smaller cuts in emissions should still be preferred to no cuts at all, as I imagine that they would reduce the peak warming and/or delay the peak for longer and/or reduce the eventual recovery time. Perhaps not by as much as we might prefer, but still better than nothing. But perhaps my intuition is off.

  • $\begingroup$ So far the atmospheric CO2 is continuing to rise at an increasing rate , so I wouldn't worry about it being reduced too rapidly. ( See Mauna Loa charts) . $\endgroup$ Jun 20, 2021 at 0:54

1 Answer 1


Yes, because carbon emissions are like a budget. The Mercator Institute has one of the most commonly cited analyses of our carbon budget:

the atmosphere can absorb, calculated from end-2017, no more than 420 gigatonnes (Gt) of CO2 if we are to stay below the 1.5°C threshold. Annual emissions of CO2 – from burning fossil fuels, industrial processes and land-use change – are estimated to be around 42 Gt per year, the equivalent of 1,332 tonnes per second. With emissions at a constant level, the budget would be expected to be used up in less than seven years from now. The budget for staying below the 2°C threshold, for its part, of approximately 1,170 Gt, would be exhausted in about 25 years.

So, just like a household or business budget, small (but persistent) reductions in spending/emissions do make a difference in the long run.


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