Prospective global warming may finally be two times warmer as forecasted climate models beneath business-as-usual framework and even if world encounters the 2°C target sea levels may soar six meters or more according to an worldwide team of researchers from 17 countries.
An global team of researchers reviewed warm periods in Earth's history over the past three and a half million years and compared carbon levels to current measurements in order to better understand the impact of even a two-degree temperature rise. In this scenario, polar ice caps could collapse and the desert could become green - effects that are underestimated in current forecasts.
The research seems to suggest that the target of 2°C set in Paris might be too small to help us avoid the devastating consequences of global warming.
These are some of the best documented global warming periods in the Earth's existence, shows Science Blog, and refer to the Holocene thermal maximum (which occurred 5,000 to 9,000 years ago), the last interglacial (that took place between 129,000 and 116,000 years ago), and the mid-Pliocene warm period (recorded some 3.3-3 million years ago). In the past, such changes in the temperature of the Earth led to drastic changes- the ice sheets in the Antarctic and Greenland melted and sea levels saw a growth of 6 meters, the Sahara Desert started getting green and species of the forests started migrating towards the poles.
Combining a wide range of measurements from ice cores, sediment layers, fossil records, dating using atomic isotopes and a host of other established paleoclimate methods, the researchers pieced together the impact of these climatic changes.
In combination, these periods give strong evidence of how a warmer Earth would appear once the climate had stabilized. "Even with just 2 degrees of warming - and potentially just 1.5 degrees - significant impacts on the Earth system are profound", he said.
The research team warns that earth now is warming at an alarming rate than it ever has, even if all carbon emissions were cut short- it would take us no less than centuries to reach normal average temperatures.
"We can expect that sea-level rise could become unstoppable for millennia, impacting much of the world's population, infrastructure and economic activity", Mix said.
Yet these significant observed changes are generally underestimated in climate model projections that focus on the near term.
The study also revealed that these effects were enhanced by what the scientists are calling "amplifying mechanisms", which are not accurately reflected by climate models and which actually make the situation even worse than expected.
Katrin Meissner, co-author of the study said, "Climate models appear to be trustworthy for small changes, such as for low emission scenarios over short periods, say over the next few decades out to 2100". She continues, "This research is a powerful call to act". The research team writes this increases the urgency with which countries need to address their emissions.
Alan Mix, co-author of the paper titled "Palaeoclimate constraints on the impact of 2°C anthropogenic warming and beyond", explained that the Paris Accords are simply not stringent enough to save the planet from the self-destructive path it is on right now.