Main objective of COP25: limit the increase in average temperature

The delegations participating in the Chilean climate change summit that is being held these days in Madrid have just two weeks to reach a binding agreement that will limit the increase in the average temperature of the planet by 1.5°C.

That is the main objective of the summit and the main challenge that the world must assume to avoid catastrophic climate change.

In October 2018, the Intergovernmental Panel on Climate Change (IPCC) published a special report, accompanied by more than 5,000 scientific references and signed by almost a hundred researchers from 40 countries, which warned of the serious consequences for humanity of an increase in the average temperature of the planet of 2°C, calling for urgent measures to limit that increase to 1.5 °C.

The report, called SR15: Global Warming of 1.5°C states that, although many of the adverse impacts of climate change are already occurring (with an increase of 1.1°C) the consequences will be much worse when warming increases to 1.5°C, something that seems irreversible, but will be devastating if 2°C is reached.

Reasons to drive climate action

According to the IPCC, the sea level rise predicted for 2100 would be 10 cm lower with a global warming of 1.5°C than with one reaching 2°C. In those 10 cm is the limit for the disappearance under the waters of many island states or the flooding of the most populated coastal strips on the planet.

Coral reefs could shrink by 70% with global warming of 1.5°C, but they would disappear forever with one of 2°C. The total melting of the Arctic during the summer would happen once per century if the average temperature rises by 1.5°C, or once per decade if it does so by up to 2°C.

According to UN experts, to avoid a 2°C increase, carbon dioxide (_CO2) emissions linked to human activity should be reduced by 45% by 2030 compared to 2010 levels, and continue to decrease until reaching zero emissions by 2050.

That means that in just 30 years any _CO2 emissions that occur as a result of any human activity will have to be compensated by removing the same amount from the atmosphere.

The threat of permafrost

Among the possible impacts that would generate a range of increase in temperatures between 1.5 ° C and 2 ° C would be the thawing of permafrost: the layer of soil that remains permanently frozen in the coldest regions of the planet and that occupies about 16% of its land surface.

Of particular concern is the melting of the Arctic soil, which before the last glaciation was covered with vegetation and which in large regions of the tundra or taiga remains frozen between one and six meters deep since the last ice age, approximately 20,000 years ago.

According to experts, the melting of that layer of permafrost would release trillions of tons of greenhouse gases such as methane: twenty times more powerful than _CO2.

The most disturbing thing, and which should serve as a stimulus to the delegations gathered at the Chile Summit in Madrid to reach an ambitious and binding agreement, is that since last summer in large regions of Alaska or Siberia permafrost has begun to thaw suddenly and much earlier than expected.

Source: The Vanguard