{"id":143940,"date":"2019-09-30T12:00:50","date_gmt":"2019-09-30T11:00:50","guid":{"rendered":"https:\/\/www.transcend.org\/tms\/?p=143940"},"modified":"2019-09-26T10:43:19","modified_gmt":"2019-09-26T09:43:19","slug":"not-convinced-on-the-need-for-urgent-climate-action-heres-what-happens-to-our-planet-between-1-5c-and-2c-of-global-warming","status":"publish","type":"post","link":"https:\/\/www.transcend.org\/tms\/2019\/09\/not-convinced-on-the-need-for-urgent-climate-action-heres-what-happens-to-our-planet-between-1-5c-and-2c-of-global-warming\/","title":{"rendered":"Not Convinced on the Need for Urgent Climate Action? Here\u2019s What Happens to Our Planet between 1.5\u00b0C and 2\u00b0C of Global Warming"},"content":{"rendered":"
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Drought is just one reason why it matters to keep global heating below 1.5C. Nic Bothma\/EPA<\/p><\/div>\n

24 Sep 2019 – <\/em>Many numbers are bandied around in climate emergency discussions. Of them, 1.5\u00b0C is perhaps the most important. At the Paris Agreement in 2015, governments agreed to limit global warming to well below 2\u00b0C and to aim for 1.5\u00b0C. By 2018, the Intergovernmental Panel on Climate Change \u2013 the UN body tasked with relaying the science of climate breakdown to the world \u2013 had made worryingly clear in a special report<\/a> how much graver the consequences of the higher number would be.<\/p>\n

Together with the University of Queensland\u2019s Ove Hoegh-Guldberg and colleagues around the world, we\u2019ve explored in newly published work<\/a> just how much sticking to 1.5\u00b0C matters.<\/p>\n

Climate breakdown is already harming livelihoods, cities and ecosystems. From heatwaves and droughts to cyclones and floods, devastating extreme weather events<\/a> are more frequent, more intense and more unpredictable than they would be in the absence of global heating. Warming and acidifying oceans are causing severe coral bleaching to occur twice as often<\/a> as in 1980, leaving many unable to recover.<\/p>\n

Shrinking habitats are increasingly forcing wildlife into conflict with human settlements<\/a>. Increasing wildfires are damaging vital carbon stores<\/a> in North America and Siberia, while the advance of spring<\/a> is throwing species who depend on each other out of sync.<\/p>\n

The more we destabilise our climate, the greater the risk to human societies and ecosystems. Even at 1.5\u00b0C of global heating, tough times are in store for the living planet. But the space between 1.5\u00b0C and 2\u00b0C of heating is a crucial battleground, within which risks to humanity and ecosystems amplify rapidly.<\/p>\n

Climate battleground<\/strong><\/p>\n

At 1.5\u00b0C of warming, about one in twenty insect and vertebrate species will disappear from half of the area they currently inhabit, as will around one in ten plants. At 2\u00b0C, this proportion doubles for plants and vertebrates. For insects, it triples.<\/p>\n

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A great many risks amplify between 1.5 and 2 degrees of warming.
Hoegh-Guldberg, Jacob, Taylor\/IPCC<\/p><\/div>\n

Such high levels of species loss will put many ecosystems across the world at risk of collapse<\/a>. We rely on healthy ecosystems to pollinate crops, maintain fertile soil, prevent floods, purify water, and much more. Conserving them is essential for human survival and prosperity.<\/p>\n

Between 1.5\u00b0C and 2\u00b0C, the number of extremely hot days increases exponentially<\/a>. Some parts of the world can also expect less rain and more consecutive dry days, while others will receive more extreme floods. Collectively, this will place agriculture, water levels and human health under severe stress \u2013 especially in southern African nations<\/a>, where temperatures will increase faster than the global average. The Mediterranean is another key area at particular risk above 1.5\u00b0C of heating, where increased drought will alter flora and fauna in a way without precedent in ten millennia<\/a>.<\/p>\n

At 1.5\u00b0C of warming, we could expect to lose between 70% and 90% of our coral reefs. While this would be catastrophic for the millions of ocean creatures and human livelihoods these beautiful ecosystems support, there would still be a chance of recovery in the long term if oceans warm slowly. But at 2\u00b0C of warming, we could kill 99% of reefs<\/a>. To be clear, this is a line that once crossed cannot be easily uncrossed. It could mean the extinction of thousands of species.<\/p>\n

Read more: What climate ‘tipping points’ are \u2013 and how they could suddenly change our planet<\/a> <\/em><\/strong><\/p><\/blockquote>\n

Arctic sea ice has been a constant on our planet for hundreds of thousands, perhaps millions of years. If we limit global heating to 1.5\u00b0C, there\u2019s a 70% chance of it remaining that way. But at 2\u00b0C, some Arctic summers will be ice-free<\/a>. Polar bears<\/a> and other species who depend on frozen sea ice to eat and breed will be left homeless and struggling to survive.<\/p>\n

Studies show that at 1.5\u00b0C, we could expect one metre of sea-level rise in 2300, with an extra 26cm at 2\u00b0C<\/a>. However, between these two levels of global heating, the risk of the Greenland and West Antarctic Ice Sheets starting a slow process of decline dramatically increases<\/a>. For the Greenland sheet, this is likeliest to happen at 1.6\u00b0C<\/a>, with the Antarctic ice sheet\u2019s tipping point<\/a> hovering not far above<\/a> this mark.<\/p>\n

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Polar bears depend on Arctic sea ice. FloridaStock\/Shutterstock<\/p><\/div>\n

If these ice sheets melt, seas could rise by up to two metres over the next two centuries<\/a>. These rises could lead to millions more people being exposed to flooding each year<\/a>. Many of those living in coastal cities, deltas, or small islands<\/a> will be faced with little option but to build upwards or relocate.<\/p>\n

Way off track<\/strong><\/p>\n

The impacts of climate breakdown are accelerating. The planet has warmed by 1.1\u00b0C since 1850-79<\/a>, but 0.2\u00b0C of this warming happened between 2011 and 2015 alone<\/a>. The last four years were the warmest in the global temperature record<\/a>.<\/p>\n

Despite knowing all the above, many country-level commitments and action are nowhere near enough<\/a> to limit warming to 2\u00b0C, let alone 1.5\u00b0C. We\u2019re heading for 2.9\u00b0C to 3.4\u00b0C of warming<\/a>. By this point, many dangerous tipping points<\/a> could be crossed, leading to rainforest die-back, deadly heatwaves, and significant sea-level rise<\/a>. Half of all insect and plant species are projected to disappear from more than half of the area they currently inhabit<\/a>, potentially causing widespread ecosystem collapse and threatening organised human civilisation itself.<\/p>\n

Read more: Five things every government needs to do right now to tackle the climate emergency<\/a> <\/em><\/strong><\/p><\/blockquote>\n

Limiting warming to 1.5\u00b0C will save the global economy trillions of dollars<\/a> in the long run, even accounting for the seemingly gargantuan cost<\/a> of transitioning our energy systems. But this is more than just an economic or academic issue \u2013 its a matter of life and death for millions of humans and animal species, and a severe threat to the well-being of billions.<\/p>\n

Tackling climate breakdown is perhaps the tallest order humanity has ever faced, and there is no simple solution. The only way forward is accepting that we must fundamentally change the way we live our lives. It won\u2019t be an easy transition, but there is no alternative if we are to preserve the well-being of humans, wildlife, and ecosystems. The coming year is vital, and there\u2019s too much at stake not to act now.<\/p>\n

_________________________________________<\/em><\/p>\n

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Rachel Warren <\/a>– Professor of Global Change, University of East Anglia <\/em><\/p>\n

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 <\/p>\n

Sally Brown <\/a>– Senior Research Fellow, University of Southampton <\/em><\/p>\n

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Republish our articles for free, online or in print, under Creative Commons license.<\/em><\/p>\n

Go to Original \u2013 theconversation.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

24 Sep 2019 – Nations are signed up to limit global heating to well below 2\u00b0C, and to aim for 1.5\u00b0C. Limiting warming to the latter matters – the future of humanity and the living world is at stake. Climate breakdown is already harming livelihoods, cities and ecosystems. From heatwaves and droughts to cyclones and floods, devastating extreme weather events are more frequent, more intense and more unpredictable than they would be in the absence of global heating.<\/p>\n","protected":false},"author":4,"featured_media":143941,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[61],"tags":[229,232,686,120,331,354,401,267,993,260,487,109,287,380,75],"class_list":["post-143940","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment","tag-activism","tag-capitalism","tag-climate-change","tag-conflict","tag-development","tag-economics","tag-environment","tag-geopolitics","tag-global-warming","tag-history","tag-human-rights","tag-politics","tag-power","tag-solutions","tag-world"],"_links":{"self":[{"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/posts\/143940","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/comments?post=143940"}],"version-history":[{"count":0,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/posts\/143940\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/media\/143941"}],"wp:attachment":[{"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/media?parent=143940"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/categories?post=143940"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/tags?post=143940"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}