{"id":16215,"date":"2018-08-07T06:47:34","date_gmt":"2018-08-07T10:47:34","guid":{"rendered":"https:\/\/pierrejoris.com\/blog\/?p=16215"},"modified":"2018-08-07T06:47:35","modified_gmt":"2018-08-07T10:47:35","slug":"planet-at-risk-of-heading-towards-irreversible-hothouse-earth-state","status":"publish","type":"post","link":"https:\/\/pierrejoris.com\/blog\/planet-at-risk-of-heading-towards-irreversible-hothouse-earth-state\/","title":{"rendered":"Planet at risk of heading towards irreversible \u201cHothouse Earth\u201d state"},"content":{"rendered":"

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Joint Press Release by the Stockholm Resilience Center, University of Copenhagen, Australian National University and the Potsdam Institute for Climate Impact Research <\/i><\/p>\n

<\/i><\/b>07\/08\/2018<\/span><\/p>\n

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Keeping global warming to within 1.5-2\u00b0C may be more difficult than previously assessed. An international team of scientists has published a study in Proceedings of the National Academy of Sciences (PNAS) showing that even if the carbon emission reductions called for in the Paris Agreement are met, there is a risk of the planet entering what the scientists call \u201cHothouse Earth\u201d conditions. A \u201cHothouse Earth\u201d climate will in the long term stabilize at a global average of 4-5\u00b0C higher than pre-industrial temperatures with sea level 10-60 m higher than today, the paper says. The authors conclude it is now urgent to greatly accelerate the transition towards an emission-free world economy.<\/b><\/span><\/p>\n

\u201cHuman emissions of greenhouse gas are not the sole determinant of temperature on Earth. Our study suggests that human-induced global warming of 2\u00b0C may trigger other Earth system processes, often called \u201cfeedbacks\u201d, that can drive further warming \u2013 even if we stop emitting greenhouse gases\u201d, says lead author Will Steffen from the Australian National University and Stockholm Resilience Centre. \u201cAvoiding this scenario requires a redirection of human actions from exploitation to stewardship of the Earth system.\u201d<\/span><\/p>\n

Currently, global average temperatures are just over 1\u00b0C above pre-industrial and rising at 0.17\u00b0C per decade.<\/p>\n

The authors of the study consider ten natural feedback processes, some of which are \u201ctipping elements\u201d that lead to abrupt change if a critical threshold is crossed. These feedbacks could turn from being a \u201cfriend\u201d that stores carbon to a \u201cfoe\u201d that emits it uncontrollably in a warmer world. These feedbacks are: permafrost thaw, loss of methane hydrates from the ocean floor, weakening land and ocean carbon sinks, increasing bacterial respiration in the oceans, Amazon rainforest dieback, boreal forest dieback, reduction of northern hemisphere snow cover, loss of Arctic summer sea ice, and reduction of Antarctic sea ice and polar ice sheets.<\/p>\n

\u201cThese tipping elements can potentially act like a row of dominoes. Once one is pushed over, it pushes Earth towards another. It may be very difficult or impossible to stop the whole row of dominoes from tumbling over. Places on Earth will become uninhabitable if \u201cHothouse Earth\u201d becomes the reality,\u201d adds co-author Johan Rockstr\u00f6m, Executive Director of the Stockholm Resilience Centre and incoming co-Director of the Potsdam Institute for Climate Impact Research.<\/p>\n

Cascade of events may tip the entire Earth system into a new mode of operation<\/b><\/p>\n

Co-author Hans Joachim Schellnhuber, Director of the Potsdam Institute for Climate Impact Research, says, \u201cWe show how industrial-age greenhouse gas emissions force our climate, and ultimately the Earth system, out of balance. In particular, we address tipping elements in the planetary machinery that might, once a certain stress level has been passed, one by one change fundamentally, rapidly, and perhaps irreversibly. This cascade of events may tip the entire Earth system into a new mode of operation.\u201d<\/p>\n

\u201cWhat we do not know yet is whether the climate system can be safely \u2018parked\u2019 near 2\u00b0C above preindustrial levels, as the Paris Agreement envisages. Or if it will, once pushed so far, slip down the slope towards a hothouse planet. Research must assess this risk as soon as possible.\u201d
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\n<\/b>Cutting greenhouse gases is not enough<\/b><\/p>\n

Maximizing the chances of avoiding a \u201cHothouse Earth\u201d requires not only reduction of carbon dioxide and other greenhouse gas emissions but also enhancement and\/or creation of new biological carbon stores, for example, through improved forest, agricultural and soil management; biodiversity conservation; and technologies that remove carbon dioxide from the atmosphere and store it underground, the paper says. Critically, the study emphasizes that these measures must be underpinned by fundamental societal changes that are required to maintain a\u00a0 \u201cStabilized Earth\u201d where temperatures are ~2\u00b0C warmer that the pre-industrial.<\/p>\n

\u201cClimate and other global changes show us that we humans are impacting the Earth system at the global level. This means that we as a global community can also manage our relationship with the system to influence future planetary conditions. This study identifies some of the levers that can be used to do so,\u201d concludes co-author Katherine Richardson from the University of Copenhagen.<\/p>\n


\nArticle:<\/b> Will Steffen, Johan Rockstr\u00f6m, Katherine Richardson, Timothy M. Lenton, Carl Folke, Diana Liverman, Colin P.Summerhayes, Anthony D. Barnosky, Sarah E. Cornell, Michel Crucifix, Jonathan F. Donges, Ingo Fetzer, Steven J. Lade, Marten Scheffer, Ricarda Winkelmann, Hans Joachim Schellnhuber (2018). Trajectories of the Earth System on the Anthropocene. Proceedings of the National Academy of Sciences (PNAS). <\/span>[DOI: 10.1073\/pnas.1810141115]<\/span><\/p>\n

Weblink to the article:<\/b> http:\/\/www.pnas.org\/content\/early\/2018\/07\/31\/1810141115<\/a><\/span><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Joint Press Release by the Stockholm Resilience Center, University of Copenhagen, Australian National University and the Potsdam Institute for Climate Impact Research 07\/08\/2018 Keeping global warming to within 1.5-2\u00b0C may be more difficult than...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[31,67],"tags":[],"class_list":["post-16215","post","type-post","status-publish","format-standard","hentry","category-climate-change","category-man-made-disaster"],"_links":{"self":[{"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/posts\/16215","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/comments?post=16215"}],"version-history":[{"count":3,"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/posts\/16215\/revisions"}],"predecessor-version":[{"id":16219,"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/posts\/16215\/revisions\/16219"}],"wp:attachment":[{"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/media?parent=16215"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/categories?post=16215"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pierrejoris.com\/blog\/wp-json\/wp\/v2\/tags?post=16215"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}