\n<\/p>\n
Our planet is sick, and its life-threatening symptoms are getting worse, a new report warns.<\/p>\n
Earth has been pushed past multiple physical and chemical boundaries crucial for keeping the world a livable place. Beyond already exceeded thresholds set by scientists for rising temperatures, biodiversity loss and chemical pollution, we have now also breached the boundary on ocean acidification. The milestone comes with grim ramifications for marine ecosystems and human livelihoods.<\/p>\n
\u201cMore than three-quarters of the Earth\u2019s support systems are not in the safe zone,\u201d Johan Rockstr\u00f6m, director of the Potsdam Institute for Climate Impact Research (PIK) in Germany, said in a statement announcing the 2025 evaluation of the planetary boundaries. \u201cHumanity is pushing beyond the limits of a safe operating space, increasing the risk of destabilizing the planet.\u201d<\/p>\n
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n
Humans and many other species evolved to thrive in the climate of the Holocene, a period that began around 10,000 years ago. But as societies industrialized and began widely burning fossil fuels in the 19th century, greenhouse gases built up in the atmosphere, trapping heat and transforming Earth and its climate in many ways besides raising global temperatures.<\/p>\n
Beginning in 2009, PIK flagged and prioritized research on nine geophysical limits that make up a sort of planetary life-support system; staying within these limits, they argue, is the best hope for maintaining the clement climatic conditions we and most of Earth\u2019s other denizens have adapted to. In 2023 researchers published a study that quantified those boundaries and established where we are in relation to them. At the time, six of the boundaries had been surpassed, with many well into what the scientists called a \u201czone of increasing risk.\u201d<\/p>\n
\u201cIt\u2019s like blood pressure,\u201d said the 2023 study\u2019s lead author Katherine Richardson, an earth systems scientist at the University of Copenhagen, in an interview with Scientific American at the time. \u201cIf your blood pressure is over 120 over 80, it\u2019s not a guarantee that you\u2019re going to have a heart attack, but it does raise the risk, and therefore we do what we can to bring it down.\u201d<\/p>\n
Among the nine boundaries is of course climate change, which is measured in part by the amount of world-warming carbon dioxide in Earth\u2019s atmosphere. Carbon dioxide concentrations reached a record global high of 422.7 parts per million (ppm) last year, compared with 280 ppm prior to the industrial revolution and the 350 ppm that many scientists consider a \u201csafe\u201d limit (which was surpassed in 1987). The burning of fossil fuels is the indisputable culprit.<\/p>\n
Fossil fuels are also behind the new boundary breaching\u2014the ocean absorbs some of the atmosphere\u2019s excess carbon dioxide, causing waters to become more acidic. Since the industrial revolution, the ocean\u2019s surface pH has dropped by 0.1; this may seem minuscule, but because the pH scale is logarithmic, it reflects roughly a 30 percent increase in acidity.<\/p>\n
Ocean acidification can have profound impacts on marine ecosystems by depleting seawater of certain carbon compounds that corals and other shell building animals need to construct their protective homes. At low enough pH levels, corals and shells can even begin to dissolve. These effects could destabilize entire ecosystems and devastate many commercially valuable species, such as oysters. A 2020 report by the U.S. National Oceanic and Atmospheric Administration found that ocean acidification would cost the country\u2019s economy billions of dollars.<\/p>\n
\u201cThe movement we\u2019re seeing is absolutely headed in the wrong direction. The ocean is becoming more acidic, oxygen levels are dropping, and marine heatwaves are increasing. This is ramping up pressure on a system vital to stabilize conditions on planet Earth,\u201d Levke Caesar, co-lead of PIK\u2019s Planetary Boundaries Science Lab, said in the new evaluation\u2019s press statement.<\/p>\n
The not-so-short list of other boundaries we\u2019ve blown past is sobering. Excess phosphorus and nitrogen from the widespread use of fertilizers flows into rivers and seas to spark toxic algal blooms. Artificial chemicals, such as plastics, dichlorodiphenyltrichloroethane (DDT) and \u201cforever chemical\u201d perfluoroalkyl and polyfluoroalkyl substances (PFAS) disruptively accumulate in food chains. Agriculture and other changes in land use strip away forests and diminish available fresh water. And as all these problems grow, more and more of Earth\u2019s biodiversity is disappearing.<\/p>\n
According to the new report, just two of the nine limits remain intact: ozone depletion and aerosols in the atmosphere. Only the former shows clear progress away from the planetary boundary, as a result of the success of the Montreal Protocol, the international agreement through which countries are phasing out chemicals that erode Earth\u2019s protective ozone layer. Aerosol emissions have declined globally\u2014partly from efforts to reduce pollution from global shipping\u2014but absent any unified policy framework for reductions, levels could easily surge back.<\/p>\n
The overall prognosis for the planet\u2019s health is poor, given that a number of countries, including the U.S. in particular, are moving away from meaningful action to tackle environmental problems.<\/p>\n
\u201cWe are witnessing widespread decline in the health of our planet. But this is not an inevitable outcome. The drop in aerosol pollution and healing of the ozone layer, shows that it is possible to turn the direction of global development. Even if the diagnosis is dire, the window of cure is still open,\u201d Rockstr\u00f6m said in the press statement. \u201cFailure is not inevitable; failure is a choice. A choice that must and can be avoided.\u201d<\/p>\n
If you enjoyed this article, I\u2019d like to ask for your support. Scientific American<\/span> has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n I\u2019ve been a Scientific American<\/span> subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm <\/span>always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n If you subscribe to Scientific American<\/span>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n In return, you get essential news, captivating podcasts, brilliant infographics, can’t-miss newsletters, must-watch videos, challenging games, and the science world’s best writing and reporting. You can even gift someone a subscription.<\/p>\n There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":" Our planet is sick, and its life-threatening symptoms are getting worse, a new report warns. Earth has been pushed past multiple physical and chemical boundaries crucial for keeping the world a livable place. Beyond already exceeded thresholds set by scientists for rising temperatures, biodiversity loss and chemical pollution, we have now also breached the boundary<\/p>\n","protected":false},"author":1,"featured_media":25599,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[58],"tags":[14347,14564,589,11002,6781,2309,14346],"class_list":{"0":"post-25598","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-acidification","9":"tag-boundary","10":"tag-earth","11":"tag-ocean","12":"tag-planetary","13":"tag-pushes","14":"tag-threshold"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/25598","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=25598"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/25598\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/25599"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=25598"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25598"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25598"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}