*Written in collaboration with Paulo Horta, professor at UFSC, who coordinates research related to environmental impacts due to climate change and marine pollution and was present at Cop 28.
A study from the University of Exeter in the UK, published last week amid the CO28 discussions, seriously warns: Five key environments that support the planet's climate stability are collapsing and could quickly worsen the climate crisis. These are the collapse of warmwater corals, melting ice in Antarctica and Greenland, melting permafrost and changes in the North Atlantic circulation.
The study (*1) involved the Brazilian researcher Marina Hirota, professor in the Department of Physics of the Federal University of Santa Catarina, whom we interviewed to explore the dimensions and meanings of the document that aims to guide the decisions of nations in the humanitarian context Need to end mining and burning of fossil fuels.
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“The report's conclusions reinforce the evidence gathered in recent years that the compromise of Greenland, Antarctica, permanently frozen areas, permafrost, tropical coral reefs and the major Atlantic ocean circulation is reaching a point of no return Turning point. With a warming of 1.5 degrees that will already be recorded in 2023 and which, according to analyzes by a group led by Dr. James Hansen (*2) should strengthen in the coming years. These environments will enter a vicious circle in which their collapse will drive climate change, increasing the impairment of their ability to function. Like Dr. “As Kaitlin A. Naughten (*3) noted, once these triggers are activated, there may be no return, as the British researcher described for the western region of Antarctica,” explains the scientist.
An unprecedented melting process is expected to occur in frozen areas, leading to sea level rise and the release of greenhouse gases, amplifying climate change. Warming ocean temperatures are expected to increase coral bleaching and dieoff, triggering a cascade of biodiversity loss. The slowing of ocean currents is likely to have direct and indirect impacts on heatwaves, droughts and other impacts of climate change.
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The most worrying thing is that these systems are connected in different ways and the engagement of each affects the others. And we must remember that all other 24 key systems on our planet will be affected by the compromise of these first five, triggering a chain reaction that accelerates processes associated with the deterioration of the climate stability of the biosphere and the disease of humanity.
After successive years of incalculable loss and damage to our environment, society and economy, highlighting the loss of millions of lives, we recognize that these changes will reach catastrophic proportions in the not too distant future. The editorial published in a major health magazine highlights 6.7 million additional deaths linked to fossil fuel burning (*4).
Looking at this entire scenario of experienced and predicted tragedies, and as Professor Marina Hirota points out, this scenario “could be much more catastrophic than the models predict”.
“The report concludes by reaffirming that there are alternative paths. These alternatives can represent positive game changers that urgently need to be prioritized, with campaigns to democratize access and subsidies improving and disseminating. Human activities are understood as part of regenerative economies, such as “Conserving natural remains, restoring ecosystems, rehabilitating our territories and producing food in an ecologically balanced way can represent models of healthy, resilient, resilient and just societies,” he assesses.
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In the current scenario, there is no room for inaction, omission or irresponsible decisions related to expansion of oil exploration. Because as the title of another document circulating at COP28 this week, the Cryosphere Report (*5), reiterates, 2 degrees (warming) is too much, and if we leave things as they are, set we continue our death march towards greater warming of 2.5°C.
Below is a brief summary of each threatened environment
Warm water corals
Of the 26 turning points identified in the study, five are in a situation that is considered dramatic. One of them is the situation of warmwater coral reefs, ecosystems that are very sensitive to climate change, in particular to the increase in the temperature of marine waters that has already been observed. And ocean acidification.
Located near the equator, these corals have undergone several bleaching processes in recent years. In doing so, they expel the socalled symbiotic algae, which causes the color change.
According to a study by the Global Coral Reef Monitoring Network (GCRMN), the world has lost 14% of its coral reefs since 2009. The data covers more than 12,000 locations surveyed in 73 countries over the past 40 years.
Coral bleaching with hot water. Photo credit: Beatrice Padovani/Reefcheck/PeldTAMSUFPE
North Atlantic circulation
The global climate is anchored, among other things, in the socalled thermohaline. This is the process that acts as a kind of heat spreader for the planet and is driven by differences in temperature and salinity of the seas between the equatorial and polar zones.
As the seas warmed, there was also an increase in temperature in the waters of the polar and temperate zones. According to scientists and researchers, the North Atlantic is undergoing this process. This will mean a slowdown in the medium term thermohalinewhich can change the weather conditions on the planet.
In this sense, it is important to highlight that 90% of the planet's heat is stored in the oceans.
However, there are already studies that indicate a slowdown of the Atlantic current system by 15%. The most affected regions are in the socalled North Atlantic Subpolar Gyre, which includes the coasts of Greenland, Labrador (Canada) and the Nordic seas.
The main reason for this change is the desalination of water as a result of the melting of nearby polar ice. The only way to mitigate changes in the North Atlantic circulation, scientists say, is to reduce greenhouse gas emissions.
Greenland meltwater
With the already consolidated increase in seawater temperatures, air and ocean currents are also becoming warmer. When they reach areas like Greenland, where there are huge sheets of ice and permafrost on the coast, they contribute to the melting of the ice.
If the Greenland ice sheet melts, in addition to the obvious rise in sea levels, changes in ocean circulation could force their way into the South Atlantic region, intensifying the El Niño phenomenon, scientists say.
This year, 2023, Greenland lost ice for the 27th consecutive year. The weather there is not “normal” either. Much of this melting was due to unexpected rainfall. And once it melts, it will be impossible to restore the ice sheet.
Antarctic melting ice
In the case of Antarctica, despite the similar situation to Greenland, it is important to highlight the numbers on the frozen continent (which is, however, slightly less cold). The year 2023 marked the lowest extent of Antarctic sea ice since 1978, when satellite measurements began.
The causes and consequences are the same: increased ocean temperatures and currents, rising sea levels and changes in ocean circulation that should alter the climate of the entire planet.
Melting ice off the coast of Antarctica. Credits: Pexels
Permafrost is melting
Finally Arctic permafrost. This special, frozen ground that covers more than 23 million square kilometers worldwide and lies beneath the surface.
According to recent studies, permafrost stores 1,700 billion tons of carbon. As it thaws, there could be local changes in the soil as well as the release of overwhelming quantities of greenhouse gases. And the permafrost layers are already melting. Over the last 30 years there has been an average temperature increase of 1.5 to 2.5 degrees Celsius.
Permafrost: frozen ground beneath the surface. Photo credit: United Nations News/Reproduction
References for further reading
1. TM Lenton, DI Armstrong McKay, S Loriani, JF Abrams, SJ Lade, JF Donges, M Milkoreit, T Powell, SR Smith, C Zimm, JE Buxton, E Bailey, L Laybourn, A. Ghadiali, JG Dyke (ed.), 2023, The Global Tipping Points Report 2023. University of Exeter, Exeter, UK.
2. Hansen, J et al. (2023). Global warming in the pipeline. Oxford Open Climate Change, 3(1), kgad008.
3. Naughten, K. et al. (2023). Inevitable future increases in melting of the West Antarctic ice shelf in the 21st century, Nature Climate Change, Volume 13: 12221228.
4. Lehtomäki, H., Rao, S. & Hänninen, O. (2023). Phaseout of fossil fuels would save millions of lives worldwide. bmj, 383.
5th ICCI, 2023. State of the cryosphere in 2023 Two degrees is too high. International Cryosphere Climate Initiative (ICCI), Stockholm, Sweden. 62 p.16