The article was originally published at The Conversation.
The University of Michigan has a Professor of Climate and Space Sciences and Engineering.
Global warming is not going to stop on a dime. If people stopped burning fossil fuels tomorrow, stored heat would continue to warm the atmosphere.
Picture a home with a heating element. The water is heated by a boiler in the house. The air in the room is heated by the radiators. After the boiler is turned off, the already heated water is still circulating through the system, heating the house. The air in the room is still warm despite the cooling down of the radiators.
This is known as committed warming. Earth has similar ways of storing and releasing heat.
Scientists are refining their understanding of how Earth's warming will affect the climate. It used to be that it would take 40 years or more for global surface air temperature to peak once humans stopped heating up the planet.
That doesn't mean the planet returns to its preindustrial climate or that we avoid disruptive effects such as sea level rise.
I am a professor of climate science, and my research and teaching focuses on the use of climate knowledge by practitioners such as urban planners, public health professionals and policymakers. The Intergovernmental Panel on Climate Change is expected to release a report on climate change in early April.
The first climate models were very simplified and only represented the atmosphere. Scientists added oceans, land, ice sheets, chemistry and biology over the years.
Carbon dioxide can be more explicitly represented in today's models. Scientists can separate the role of heat in the ocean from the role of carbon dioxide in the atmosphere.
Increasing concentrations of greenhouse gases keep the boiler on and raise the temperature. Most of the heat is stored in the oceans, which take on the role of the radiators. The heat is distributed by weather and currents.
The current understanding is that if all of the heating to the planet caused by humans was eliminated, the global surface air temperature would peak in 10 years. Over the years, the previous estimate of 40 or more years has been widely used.
It is important to note that this is only the peak, when the temperature starts to stabilize, not the beginning of rapid cooling or a reversal of climate change.
There is enough uncertainty to justify caution about exaggerating the significance of the new research. The concept of peak warming was applied by the authors. The global surface air temperature is not the best measure of climate change. The idea of instantly cutting off human-caused heating is unrealistic and would involve a lot more than just ending fossil fuel use.
Even if the air temperature were to peak and stabilizing, ice melting and sea level rise would continue to evolve from the accumulated heat. Some of these could cause a release of carbon dioxide and methane from the frozen high-latitude areas.
It is important to consider how far into the future studies like this one look.
The ocean will continue to store heat and exchange it with the atmosphere. The excess heat that has been accumulating in the ocean since preindustrial times would affect the climate for another 100 years or more if emissions stopped.
The ocean has currents and will not diffuse its excess heat into the atmosphere. As the temperature changes, there will be ups and downs.
The amount of carbon dioxide in the atmosphere is influenced by the amount of carbon dioxide absorbed by the oceans.
The possibility that a policy intervention might have measurable impacts in 10 years could motivate more aggressive efforts to remove carbon dioxide from the atmosphere. It would be great to see policy interventions having present benefits.
Today, countries aren't very close to ending fossil fuel use. All of the evidence points to rapid global warming in the coming decades.
The better off humanity will be because the less carbon dioxide humans release, the better. Climate change and human behavior point to the need to accelerate efforts to reduce greenhouse gas emissions and to adapt to this warming planet now, rather than just talking about how much needs to happen in the future.
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