Scientists have prognosticated that if current trends continue apropos of climate change, Earth would be heading towards a ‘global tipping point’, a ‘point of no return’, and has called for urgent action to avoid an existential threat to our civilization.
Published in the journal Nature, they assert that the evidence for this irreversible change to Earth’s environmental systems is unassailable and we are now in a state of a ‘planetary scale emergency’.
The tipping point can be defined as a threshold beyond which the changes are not reversible, such as the loss of the Amazon rain forests, melting of the ice sheets and thawing of permafrost, which would render certain regions of the planet uninhabitable, the authors commented.
They argue in their paper about the bleak estimates for the future, “The intervention time left to reach the tipping point may be close to zero, however the reaction time to achieve zero net emissions is in the order of 30 years”.
Research led by Timothy Lenton, professor of climate change and Earth system science at the University of Exeter, in England, has identified nine areas where the tipping points may already be underway, like the large scale destruction of the Amazon forests, reduction of the Arctic ice sheets, widespread extirpation of coral reefs, melting of the Greenland and the Antarctic ice sheets, thawing of permafrost, large scale deforestation and a slowdown of ocean circulation.
What’s concerning is that these events are interconnected and changes in one can lead to a cascading impact on others, thereby exacerbating the current situation; as evidence shows that the Arctic ice is warming at least twice as quickly as the global average, which in turn increases the warming further as there is less ice to reflect the sunlight off the planet.
Thawing of the permafrost is releasing huge quantities of methane and CO2 into the atmosphere, which otherwise stays frozen throughout. This warming has also impacted many insect populations and has also led to extensive conflagration of the forests, turning them into a source of carbon rather than absorbing carbon from the atmosphere had the fires not destroyed them.
The researchers say the climate change models are more sensitive to initial conditions and small changes can have huge impacts and that we may be closer to the tipping point, as suggested by the collapse of the West Antarctic ice sheet and from a switch from rain forest to Savannah.
The idea of climate change has been floated around for many years now by the IPCC (Intergovernmental panel on climate change). Back then they expected large scale havoc only if the warming exceeded 5 degree Celsius above pre-industrial levels, but latest reports have been more alarming, which concludes that tipping points can happen even if the warming is between 1 and 2 degree Celsius.
Currently, average temperatures are about 1 degree Celsius above the pre-industrial era and its rise is inexorable. Scientists have predicted that the domino effect will in fact happen if temperatures rise more than 2 degree Celsius above pre-industrial levels.
They have modeled how these various events can be interconnected: how loss of forests, melting ice and increased microbial respiration can form a feedback loop to make the existing situation worse.
Though they agree that there are limits to understanding when the tipping point can occur, the effect it can have on our planet once the threshold is crossed would be so huge that ignoring it would cause great peril to our civilization.
The Paris agreement has set a goal to limit the increase in temperature to 1.5 degree Celsius by 2100 however global efforts by countries towards this is nowhere close enough to reach the target and current trends indicate that temperatures can rise up to 3.2 degree Celsius by 2100.
With greenhouse gases already reaching a record high in 2018, according to recent report by the WMO (World Meteorological Organization), with no sign of abating, reaching 407.8 ppm, it is indeed looking bleak.
Researchers say we can still hope to keep the rising temperatures below 1.5 degree Celsius, however it requires a global coordinated effort to reduce the emission of greenhouse gases as ignoring it would be a scourge for humanity.