In [this page](https://www.princeton.edu/news/2013/11/24/even-if-emissions-stop-carbon-dioxide-could-warm-earth-centuries) it says “scientific consensus is temperature would remain constant or decline if emissions were suddenly cut to zero”. There are scenarios in page 74 of this [IPCC report](https://www.ipcc.ch/site/assets/uploads/2018/02/SYR_AR5_FINAL_full.pdf). We can see that in some scenarios CO2 levels are high but temperature remains same or declines. Also, we know that when we cut the emissions CO2 levels in the atmosphere will remain high for centuries. How do these projections work?
I thought earth was getting warmer because of the high levels of CO2 in our atmosphere. In the scenario that we cut emissions, there will still be high levels of CO2 in our atmosphere but many scientists says temperature won’t go up. What am I missing?
Edit: I believe I haven’t made my point clear. Of course CO2 levels [will start to decrease](https://ei.lehigh.edu/learners/cc/readings/ifemmision.pdf) when we cut emissions. However, in the last century, temperature on earth’s atmosphere were increasing due to the greenhouse gases(ghg) in our atmosphere. And when we stop emitting these gases, we will still be having too much ghg in our atmosphere. They will **slowly** be captured by plants and ocean. However, the claim is that even with this high levels, [temperature will stop increasing](https://www.nature.com/articles/ngeo813). What is the difference between having high ghg percentage on atmosphere while also emitting, and having high amount of ghg while not emitting?
In: Earth Science
If you only look at CO2 and incoming sunlight you reach a temperature equilibrium very quickly. CO2 reduces the rate of heat leave the earth, but if you look at the temperature over a day the temperature rises when the sun is up and drops when it is down, so change just from CO2 is one that is reached within days, I certainly occur in a year and I assume the temperature in the report changes in average temperature over a year.
So constant CO2 levels would result in a constant temperature. It I not the case that adding CO2 today has a direct effect that increases the temperature over decades.
There is also an indirect effect where the higher temperature changes the earth
An example is warmer winter result in less snow, less snow reflects away less light and it gets warmer. If the artic gets warmer organic matter that is today frozen starts to melt and you get CO2 and methane released from it.
So even if we do not release any more CO2 the temperature can rise because of how it changes Earth and it is the effect that can take decades. The CO2 level can also rise because of the change that happens on earth. CO2 can also drop as a planet and even animal can bind it and remove from the atmosphere. Coral and another sea animal with hard shells build it up from carbon and another element. It is a way an enormous amount of CO2 can be bound even if it can be a slow process.
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