The global temperature of the earth will increase by two degrees only due to greenhouse gases in the atmosphere.
Scientists at the University of Nanjing, Lawrence Livermore National Laboratory (LLNL), and Texas A&M University used climate observations and simulations to estimate the effect of greenhouse gases on the planet’s temperature. The new result is higher than the previous ones since it takes into account changes in the geographic structure of surface warming.
Typically, sustained warming is estimated on the assumption that changes in the future will largely follow changes in the past. But now we know that this is a wrong assumption.
Mark Zelinka, LLNL atmospheric scientist
Most of the planet’s surface has warmed up, but in some regions, such as the Southern Ocean, this has not happened. The lack of warming heating contributes to the formation of low clouds above these regions, which reflect sunlight back into space and greatly cool the planet. Over time, these regions will heat up. When this happens, the low clouds will decrease, allowing the Earth to absorb more sunlight and contribute to additional warming.
The team found that future warming will be roughly+ 2.3 degrees: that’s above pre-industrial levels. This figure exceeds the limits set in the Paris Agreement.
The results show that humankind most likely produced enough carbon dioxide to exceed the 2 ° C threshold. As net emissions approach zero, the researchers note, the rate of continued sustained warming will be very low. This means that if humanity can bring net emissions to almost zero in the near future, then it may take centuries for the global temperature to rise to two degrees.