How Much Global Warming Is Already Unavoidable?
A new study from researchers at the University of Washington suggests the warming effects of greenhouse gasses (GHG) are already so “baked in” to the climate system that the Earth would continue to warm even if all emissions completely stopped, committing us to peak temperatures 5 to 10 years before actually experiencing them.
The study used a climate model to test what would happen to the Earth’s atmosphere if all emissions were to suddenly stop, modeling them along eight different emissions pathways to test variances.
Previous studies have explored what would happen if all carbon dioxide emissions stopped, but this is the first to include other GHG, like methane and particle pollution.
Obviously, stopping all emissions is unrealistic, but the researchers used it as an example of the best-case scenario to establish a lower limit for future warming.
The team found simultaneously stopping all GHG emissions would still result in the atmosphere warming by 0.2 degrees Celsius, with an effect that could last up to two decades.
Ultimately, the model showed past emissions have already committed the Earth to reaching peak temperatures about 5 to 10 years before we actually experience them.
What’s behind it:
Different emissions warm or cool the planet, depending on their form.
Particulate pollution reflects sunlight and therefore has a slight cooling effect, resulting in the slight bump observed in atmospheric temperatures if GHG are removed altogether.
Why it matters:
The researchers say the findings show what amount of warming already can’t be avoided, and makes rapidly reducing emissions all the more pressing.