The world woke up this Monday with the announcement of “a red alert for humanity.”
The United Nations Intergovernmental Panel on Climate Change (IPCC) released its long-awaited report on how global warming will change our planet in the coming decades.
This is an analysis of more than 14. 000 scientific articles, the most complete to date.
According to the scientists’ conclusions, continued greenhouse gas emissions could breach a key global temperature limit in just over a decade.
They also believe that “it is not possible to rule out” a rise in sea level that approaches 2 meters at the end It is from this century.
In BBC Mundo we share 5 of the most important revelations of the document, according to the BBC Environment correspondent, Matt McGrath.
1. Climate change is widespread, rapid and intensifying (and it depends on us)
The dangers of global warming are no longer something distant, something that impacts people who live in other distant places: it is already part of our daily lives.
“ Climate change is not a problem of the future, it is here and now and affects all regions of the world “, said Friederike Otto, researcher at the University of Oxford , and one of the many authors of the IPCC report.
The strength of the claims that scientists are now making about their projections is the true strength of this new publication.
The phrase “very likely” appears 42 times in the 40 pages of the “Resu menu for legislators ”. In scientific terms, that means it’s a 90 – 100% sure will happen.
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The clearest of these points refers to humanity’s responsibility for climate change.
There are no more mistakes, we are the ones who can stop this situation .
2. Temperature may rise more than expected
When the latest IPCC report on climate change was published in 2013, a temperature increase of 1.5 ° C was considered as a safe global limit for warming.
But in the political negotiations leading to the Paris climate agreement in 2015, many developing countries and island states pushed for a lower temperature limit, arguing that it was a matter of survival for them.
A special report on 2018 showed that the advantages of staying below that limit were huge compared to a world 2 ° C warmer.
Getting there would require cutting carbon emissions in half, essentially, for 2030, and achieve net zero emissions by 2050.
Otherwise, the limit would be reached between 2030 Y 2052.
This new report reaffirms this finding. In all scenarios, the threshold is reached at 2030 .
If emissions are not controlled, the 1.5 ° C rise could be reached in about a decade.
While the situation is very dire, it is not a sudden drop in calamity.
“The 1.5 ° C threshold is a politically important threshold, of course, but from a climatic point of view, it is not the edge of a cliff. in which, once we exceed 1.5 ° C, everything will suddenly become very catastrophic, “explains Amanda Maycock, a scientist at the University of Leeds.
“The lowest emissions scenario that we evaluate in this report shows that the level of warming stabilizes around or below 1, 5 ° C later in the century. If we went that way, then the impacts would be significantly avoided, ”he says.
3. Sea level will continue to rise, no matter what we do
In the past, IPCC reports had been criticized for being too conservative to the time to assess the risk of sea level rise.
The lack of a clear investigation caused previous reports to exclude the possible impacts of melting layers of Greenland and Antarctic ice.
Not this time.
, [ 2.400 miles de millones de toneladas de CO2 emitimos los humanos hasta ahora. ], [ 500 miles de millones más dejaría el 50% de posibilidades de permanecer por debajo de 1,5 °C. ], [ 40 miles de millones de toneladas CO2 emite la humanidad cada año. ], Source: Source: IPCC, Image: “data-lazy-src =” https://ichef.bbci.co.uk/news/amp / idt2 / 470 / 3a2af 83F-40 b – 5655 – 915F – 812to5655 d 74 f? is-pending-load = 1 “src =” https://ichef.bbci.co.uk/news/amp/ idt2 / 380 / 3a2af 83F-041 b – 4839 – 976F-812to5655 d 74 f “>
The report now shows that, under current scenarios, seas could rise above the likely range, rising as much as 2 m by the end of this century and as much as 5 m by 2150.
While these are unlikely figures, they cannot be ruled out under a very broad scheme of high greenhouse gas emissions.
It is quite a negative scenario, but even if we control emissions and maintain temperatures s around 1.5 ° C for the year 2100, the waters will continue to rise in the future.
“The danger behind these sea level rise numbers is very scary in the long run, ”says Malte Meinshausen, a professor at the University of Melbourne and another of the report’s authors.
“The document shows that even with 1.5 ° C warming, we are looking at two to three meters of sea level rise and in other scenarios it is much higher. That is just scary, because it may not be at the end of our life, but it is right around the corner and it will compromise this planet. ”
Even if if sea level rise were relatively slight, it would have unavoidable side effects.
“With the gradual rise in sea level, these extreme events of the sea level that have occurred in the past, only once per century, will occur more frequently in the future “, Says Valérie Masson-Delmotte, co-chair of the IPCC working group that prepared the new report.
“Those that occurred only once per century in the past are expected to occur once or twice per decade by mid-century. The information we provide in this report is extremely important to consider and prepare for these events. ”
4. The CO2 Findings
Scientists have long been concerned that our planet’s climate could be more sensitive to carbon dioxide than what they thought.
Generally, experts use a term called “ equilibrium climate sensitivity ”to express the range of warming that could occur if CO2 levels were to double.
In the last report, in 2013, this range ranged from 1.5 ° C and 4.5 ° C, without a best estimate.
This time, the margin has been narrowed and the authors choose 3 ° C as the most probable.
Why is this important? so much?
“Now we can restrict this number to a good degree of certainty and then we can use it to make much more accurate predictions, “says Piers Forster, a professor at the University of Leeds and another author of the report.
” From that way, we know that the net zero will actually comply. ”
5. The role of methane
Another big surprise in the report is the role of methane, another gas behind global warming.
According to the IPCC, around 0.3 ° C out of 1.1 ° C of which the world has already warmed is the result of methane.
Addressing those emissions, coming from the oil and gas industry, agriculture and rice cultivation, could be a big win in the short term.
“The report nullifies any remaining debate on the urgent need to reduce methane pollution, especially from sectors such as oil and gas, where reductions available are faster and cheaper, ”says Fred Krupp of the United States Environmental Defense Fund.
“When it comes to overheating of our planet, every fraction of a degree matters, and there is no faster and more achievable way to slow the rate of warming than by reducing man-made methane emissions. ”
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