{"id":123498,"date":"2018-12-10T12:00:14","date_gmt":"2018-12-10T12:00:14","guid":{"rendered":"https:\/\/www.transcend.org\/tms\/?p=123498"},"modified":"2018-12-17T09:53:14","modified_gmt":"2018-12-17T09:53:14","slug":"cop24-heres-what-must-be-agreed-to-keep-warming-at-1-5c","status":"publish","type":"post","link":"https:\/\/www.transcend.org\/tms\/2018\/12\/cop24-heres-what-must-be-agreed-to-keep-warming-at-1-5c\/","title":{"rendered":"COP24: Here\u2019s What Must Be Agreed to Keep Warming at 1.5\u00b0C"},"content":{"rendered":"
\"\"<\/a>

The calm before the storm. Ricardo Tongo\/EPA<\/p><\/div>\n

3 Dec 2018 – <\/em>The Paris Agreement of 2015 has a central aim to keep global temperature rise this century well below 2\u00b0C above pre-industrial levels and to \u201cpursue efforts\u201d to limit the temperature increase even further to 1.5\u00b0C. This is an ambitious aim \u2013 global temperatures are rapidly approaching the 1.5\u00b0C target<\/a> and the 2\u00b0C limit is not far away.<\/p>\n

The path to 1.5\u00b0C requires that the world achieve zero emissions before 2050. It is imperative, therefore, that we stop burning fossil fuels, known as mitigation. However, our present trajectory suggests we\u2019re not on track. COP24 can\u2019t take its eye off this ball \u2013- there is no long-term plan that doesn\u2019t include zero fossil-carbon emissions. The scientific consensus is that we need to reach \u201cnet zero\u201d CO\u2082 emissions by 2050. But to tack closer to a scenario of 1.5\u00b0C warming, COP24 should set this target for 2035.<\/p>\n

\"\"<\/a>

Black, observed temperatures; blue, probable range from decadal forecasts; red, retrospective forecasts; green, climate simulations of the 20th century.
The Met Office<\/p><\/div>\n

Carbon removal and non-CO<\/strong>\u2082<\/strong> emissions<\/strong><\/p>\n

The United Nations, in the IPCC Special Report on Global Warming of 1.5\u00baC<\/a> has accepted that there isn\u2019t any obvious pathway to zero emissions in such a short time frame, so they have pegged their hopes on NETs \u2013 Negative Emissions Technologies. These approaches include carbon capture and storage (CCS), which involves sucking CO\u2082 from the air and storing it deep underground.<\/p>\n

Carbon removal along these lines is the second imperative for COP24 in Katowice. Globally we emit around 40 billion tonnes of CO\u2082 annually<\/a>, so net zero CO\u2082 by 2050 will require CO\u2082 removal of this scale, starting immediately.<\/p>\n

Read more: Explainer: what is carbon capture and storage?<\/a> <\/em><\/strong><\/p><\/blockquote>\n

But CO\u2082 isn\u2019t the only problem. We emit other greenhouse gases such as methane, nitrous oxide and chlorofluorocarbons (CFCs) which all contribute to climate change<\/a>. Methane is on the rise<\/a> and is 84 times more potent<\/a> as a greenhouse gas than CO\u2082.<\/p>\n

It comes from cows, and it leaks from oil wells and coal mines as \u201cfugitive methane<\/a>\u201d. It is also seeping out of the melting permafrost<\/a> in the Arctic. This is a worrying form of \u201cpositive feedback\u201d where global warming causes the further release of gases that cause further warming.<\/p>\n

Nitrous Oxide, which is 300 times more potent than CO\u2082, is rising too<\/a>, caused by modern agriculture<\/a>. And the concentration of refrigerant gases, such as CFCs, which are thousands of times more potent than CO\u2082, is not falling as fast<\/a> as we\u2019d hoped. So COP24 has a third imperative, to prevent the rise of non-CO\u2082 greenhouse gases. If we can stabilise non-CO\u2082 greenhouse emissions at present day levels we\u2019ll be doing well, but concentrations are rising fast.<\/p>\n

\"\"<\/a>

Limiting warming to 1.5\u00b0C or 2\u00b0C requires mitigation (energy efficiency and renewable generation) and CO\u2082 removal. MCC<\/p><\/div>\n

Desperate times, desperate measures<\/strong><\/p>\n

All of this is going to be hard work. We\u2019re failing to cut down our emissions, the technologies for NETs don\u2019t exist at any meaningful scale, yet and there are no political drivers in place to enforce their deployment<\/a>. There is also a real risk of a dramatic rise in methane<\/a> in the near future. COP24 will have to consider emergency plans.<\/p>\n

One such plan is very controversial. There are so-called \u201cgeoengineering\u201d technologies which can be used to cause changes in global temperatures. One of these is Solar Radiation Management (SRM), which involves injecting tiny aerosol particles high in the atmosphere where they reflect sunlight into space.<\/p>\n

We know from the eruption of Mount Pinatubo in 1991 that stratospheric aerosols caused a cooling of around 1\u00b0C<\/a> over a year. The northern winter of 1992 saw a dramatic increase in sea ice and a stalling of glacial melting. SRM technologies exist and the first sun-dimming experiments<\/a> are underway.<\/p>\n

\"\"<\/a>

A proposed SRM technique which would inject sulphate aerosols into the atmosphere. Hugh Hunt\/Wikimedia Commons, CC BY-SA<\/p><\/div>\n

There is a realistic possibility that deploying SRM can buy us some time to enact the essential measures needed to stop warming at or before 1.5\u00b0C. The discussions at COP24 must keep all options on the table, and as unpalatable as geoengineering technologies might seem, their deployment may prove to be unavoidable.<\/p>\n

The indicators are all in the danger zone. We are seeing increasing Arctic temperatures<\/a>, rapid loss of Arctic sea ice<\/a>, reduced Arctic reflectivity<\/a>, rapidly melting ice shelves<\/a> and methane release from permafrost. These are leading to rapidly rising sea levels<\/a>, coastal flooding<\/a> and storm surges<\/a>, increased hurricane and storm activity<\/a>, dry and hot conditions conducive to wildfires<\/a>, and drought and crop failure<\/a>.<\/p>\n

The urgency for decisive action is the imperative for COP24. The UN must press on with four major strands for meeting the Paris 1.5\u00b0C target:<\/p>\n

    \n
  1. Reduce fossil carbon emissions.<\/li>\n
  2. Remove carbon from the atmosphere (NETs).<\/li>\n
  3. Halt the rise of emissions of non-CO\u2082 greenhouses cases (Methane, Nitrous oxide, CFCs).<\/li>\n
  4. Investigate techniques for geoengineering, including Solar Radiation Management.<\/li>\n<\/ol>\n

    All four of these must proceed simultaneously and in parallel. COP24 must make this perfectly clear. There is utmost urgency and no time to \u201cwait and see\u201d.<\/p>\n

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

    \"\"<\/a><\/em><\/p>\n

     <\/p>\n

    Hugh Hunt <\/a>– Reader in Engineering Dynamics and Vibration, University of Cambridge <\/em><\/p>\n

     <\/p>\n

    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":"

    1.\tReduce fossil carbon emissions.
    \n2.\tRemove carbon from the atmosphere (NETs).
    \n3.\tHalt the rise of emissions of non-CO\u2082 greenhouses cases (Methane, Nitrous oxide, CFCs).
    \n4.\tInvestigate techniques for geoengineering, including Solar Radiation Management.
    \nAll four of these must proceed simultaneously and in parallel. COP24 must make this perfectly clear. There is utmost urgency and no time to \u201cwait and see\u201d.<\/p>\n","protected":false},"author":4,"featured_media":123504,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[225,82,61],"tags":[],"class_list":["post-123498","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-spotlight","category-united-nations","category-environment"],"_links":{"self":[{"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/posts\/123498","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=123498"}],"version-history":[{"count":0,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/posts\/123498\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/media\/123504"}],"wp:attachment":[{"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/media?parent=123498"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/categories?post=123498"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.transcend.org\/tms\/wp-json\/wp\/v2\/tags?post=123498"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}