UN climate experts warn: sea level rise has accelerated and is already unstoppable

It is unstoppable and accelerating. Sea level rise has been triggered by melting at the northern and southern ends of the planet, concludes the IPCC, the panel of scientists that under the umbrella of the UN analyzes the impacts of climate change generated by human action. The greenhouse gases emitted by humans so far mean that melting ice and sea level rise will continue beyond this century, the IPCC concludes in a report presented on Wednesday.

The dilemma this generation now faces is how big the mortgage — which also includes more frequent extreme weather events, threats to food security and impacts on biodiversity — will be left to the next. Whether it is a lower load, experts stress, will depend on how quickly those gases that overheat the planet and that are mainly linked to fossil fuels are no longer emitted. Hoesung Lee, president of the IPCC, on Wednesday urged countries to reduce their gases so that impacts that can no longer be eliminated are cushioned and are “more manageable for the most vulnerable people.” Because, as the IPCC points out, “the most exposed and vulnerable people are often those with the least responsiveness.”

This generational dilemma, which is raised through a special IPCC report, comes in an intense week in the battle against climate change. Following the massive student marches on September 20 and the UN summit in New York, a large global protest against inaction on warming is expected on Friday. The special report of the Intergovernmental Panel on Climate Change on Warming and Oceans is part of a series of thematic analyses. This international group of experts reviews and brings together knowledge about climate change based on published scientific studies. On this occasion, more than 100 authors from 36 countries have participated, who have reviewed some 7,000 publications.

“Sea level rise has accelerated due to the combined increase in ice loss from the Greenland and Antarctic layers,” the study concludes. The loss of ice in Antarctica due to the increase in temperature in the period between 2007 and 2016 tripled compared to the previous decade; in Greenland it doubled.

That accelerated thaw has led to a faster rate of sea level rise, up to 2.5 times faster in the last decade than the average of the last century. But the projections made by the report speak of a problem that will be accentuated, even in the event of compliance with the Paris Agreement, which states that the average increase in the planet’s temperature should not exceed two degrees compared to pre-industrial levels. In the most optimistic scenario – that of compliance with the two degrees set by Paris – the IPCC forecasts a sea level rise of 43 centimeters by 2100 (between 1902 and 2015 it was 16 centimeters). In the most adverse scenario – that emissions continue to grow as before – the rise in sea level would reach up to 84 centimeters and could exceed the meter. In addition, over the next few centuries that pace will continue to pick up speed and intensity.

The analysis highlights the “climate-related hazards” to which coastal populations are exposed: tropical cyclones, extreme sea levels, flooding or ice loss. And remember that in the low-lying coastal areas currently lives about 10% of the world’s population (680 million people). In addition, an additional 65 million people reside in small island States. And almost another 10% of the population (670 million) lives in high mountain regions, another of the areas analyzed in the report.

Increase in extreme events

Those nearly 1.5 billion people are in the red zone of climate impacts related to oceans and water. Impacts that come, for example, by the combination of sea level rise and storms or cyclones. The report warns that by 2050 “extreme sea level events” that until now were considered exceptional and occurred once every century will become commonplace and will occur “at least once a year” in many places on the planet. “Especially in tropical regions”, but also in areas such as the Mediterranean. The IPCC also forecasts an increased frequency of marine heat waves and extreme El Niño and La Niña events.

The study also analyzes adaptation actions (mainly investments) to fight against the rise of the sea that can engulf coastal cities. And he explains that those investments can be profitable for densely populated urban areas (New York, for example, has a plan to invest $10 billion in defenses). But it is very difficult for rural and poorer areas, such as small island states, to take them on.

The problem is not just rising sea levels. Associated with meteorological phenomena is the increase in water temperature – which since 1970 has grown steadily – and other problems derived from climate change. The analysis suggests that during the twenty-first century the oceans will reach “unprecedented conditions” due to the increase in temperature, greater acidification and the decrease in oxygen. This will have an impact, for example, on fisheries, affecting “livelihoods and food security” of communities that depend on marine resources to survive.

“Fish stocks will move towards the poles to locate their preferred temperatures; this will particularly affect tropical countries in terms of fisheries, but in Europe we have seen mackerel and cod already moving northwards,” Oxford University Biology Professor Alex Rogers said by email. “Fish also get smaller as temperatures rise,” he adds about the effects on fishing performance.

IMPACTS ON GLACIERS

The loss of glaciers also influences sea level rise. But, in addition, it has consequences beyond the coasts. This loss supposes, explains the IPCC, an alteration of “the availability and quality of fresh water”, which has implications for agriculture and the production of hydroelectric energy.

Another phenomenon that is analyzed is the disappearance of permafrost (the permanently frozen layer of soil) due to heating. Experts predict that it will continue to decrease, which in turn causes the greenhouse gases that keep this type of soil to be released.

All these changes away from the coast will lead to a significant increase in forest fires during the twenty-first century in most tundra and boreal regions and also in some mountainous regions, the IPCC warns.

Source: The Country