What would happen to the climate if we were to stop emitting carbon dioxide today, right now? Would we return to the climate of our elders?
The simple answer is no. Once we release the carbon dioxide stored in the fossil fuels we burn, it accumulates in and moves among the atmosphere, the oceans, the land and the plants and animals of the biosphere. The released carbon dioxide will remain in the atmosphere for thousands of years. Only after many millennia will it return to rocks, for example, through the formation of calcium carbonate – limestone – as marine organisms’ shells settle to the bottom of the ocean. But on time spans relevant to humans, once released the carbon dioxide is in our environment essentially forever. It does not go away, unless we, ourselves, remove it.
In order to stop the accumulation of heat, we would have to eliminate not just carbon dioxide emissions, but all greenhouse gases, such as methane and nitrous oxide. We’d also need to reverse deforestation and other land uses that affect the Earth’s energy balance (the difference between incoming energy from the sun and what’s returned to space). We would have to radically change our agriculture. If we did this, it would eliminate additional planetary warming, and limit the rise of air temperature. Such a cessation of warming is not possible.
So if we stop emitting carbon dioxide from burning fossil fuels today, it’s not the end of the story for global warming. There’s a delay in air-temperature increase as the atmosphere catches up with all the heat that the Earth has accumulated. After maybe 40 more years, scientists hypothesize the climate will stabilize at a temperature higher than what was normal for previous generations.