{"id":925,"date":"2009-10-27T20:36:55","date_gmt":"2009-10-28T00:36:55","guid":{"rendered":"http:\/\/www.easterbrook.ca\/steve\/?p=925"},"modified":"2009-10-27T20:36:55","modified_gmt":"2009-10-28T00:36:55","slug":"debunking-myths-or-teaching-the-basics","status":"publish","type":"post","link":"http:\/\/www.easterbrook.ca\/steve\/2009\/10\/debunking-myths-or-teaching-the-basics\/","title":{"rendered":"Debunking myths or teaching the basics?"},"content":{"rendered":"<p>Each time you encounter someone trying to claim human-induced global warming is a myth (e.g. because &#8220;Mars is warming too!&#8221;), you can save a lot of time and energy by just saying, oh yes, that&#8217;s myth #16 on the standard list of misunderstandings about climate change. Here&#8217;s <a title=\"Skeptical Science Myth List\" href=\"http:\/\/www.skepticalscience.com\/argument.php\" target=\"_blank\">the list<\/a>, lovingly and painstakingly put together by John Cook.<\/p>\n<p>Once you&#8217;ve got that out of the way, you can then challenge your assailant\u00a0to identify a <a title=\"Here's one well reasoned argument: 350ppm\" href=\"http:\/\/www.350.org\/about\/science\" target=\"_blank\">safe level of carbon dioxide<\/a> in the atmosphere, and to get them to give evidence to justify that choice. If they don&#8217;t feel qualified to answer this question, then you get to a teachable moment. Take the opportunity to teach your assailant\u00a0the difference between greenhouse gas <em>emissions<\/em> and greenhouse gas <em>concentrations<\/em>. That&#8217;s the single most important thing they have to understand. Here&#8217;s why:<\/p>\n<ul>\n<li>We <a title=\"This number is known as the climate sensitivity question\" href=\"http:\/\/en.wikipedia.org\/wiki\/Climate_sensitivity\" target=\"_blank\">know<\/a> that the earth warms by somewhere between 2 and 4.5\u00b0C (with a best estimate of about 3\u00b0C)\u00a0for each doubling of CO2 <em>concentrations<\/em> in the atmosphere (this was first <a title=\"the work of Svante Arrhenius\" href=\"http:\/\/en.wikipedia.org\/wiki\/Svante_Arrhenius\" target=\"_blank\">calculated<\/a> over 100 years ago. The number has been refined a little as we&#8217;ve come to understand the physical processes better, but only within a degree or two)<\/li>\n<li>CO2 is unlike any other pollutant: once it&#8217;s in the atmosphere it stays there for centuries (more specifically, it stays in the carbon cycle, being passed around between plants, soil, oceans, and atmosphere. But anyway, it only ever goes away when it eventually gets laid down as a new fossil layer, e.g. at the bottom of the ocean).<\/li>\n<li>The earth&#8217;s temperature only responds slowly to changes in the level of greenhouse gases in the atmosphere. That means that even though we&#8217;ve seen warming of around 0.7\u00b0C over the last century, we&#8217;re still owed at least that much again due to the CO2 we have already added to the atmosphere.<\/li>\n<li>The temperature is not determined by the amount of CO2 we\u00a0<em>emit<\/em>; it&#8217;s determined by the total <em>accumulation<\/em> in the atmosphere &#8211; i.e. how thick the &#8220;blanket&#8221; is.<\/li>\n<li>Because the carbon stays there for centuries, all new <em>emissions<\/em> increase the concentration, thus compounding the problem. <strong>T<\/strong><strong>he only <\/strong><em><strong>sustainable<\/strong><\/em><strong> level of net greenhouse gas emissions from human activities is zero<\/strong>.<\/li>\n<li>If we ever manage to get to the point where <em>net<\/em> emissions of greenhouse gases from human activities is zero, the planet will eventually (probably, over centuries) return to pre-industrial atmospheric concentration levels (about 270 parts per million), as the carbon gets reburied. During this time, the earth will continue to warm.<\/li>\n<li>Net emissions is, of course, the difference between gross emissions and any carbon we manage to remove from the system artificially. As no technology currently exists today for reliably and permanently removing carbon from the system, it would be prudent to aim for zero gross emissions. And the quicker we do it, the less the planet will warm in the meantime.<\/li>\n<li>And 3\u00b0C global average temperature is about the <a title=\"Wikipedia graph of paleoclimate temperatures\" href=\"http:\/\/en.wikipedia.org\/wiki\/File:All_palaeotemps.png\" target=\"_blank\">difference<\/a> between the last ice age (which ended about 12,000 years ago) and today&#8217;s climate. In the last ice age there were ice sheets 0.5km thick over much of North America and Europe. Now imagine how different the earth will be with a further 3\u00b0C of warming.<\/li>\n<\/ul>\n<p>Okay, so that might be a little bit too much for just one teachable moment. What we really need is a simple elegant tool to illustrate all this. Anyone up to building an interactive visualization? <a title=\"Sterman's bathtub dynamics visualization tool\" href=\"http:\/\/scripts.mit.edu\/~jsterman\/climate\/master\/\" target=\"_blank\">John Sterman tried,<\/a> but I don&#8217;t rate his tool high on the usability scale.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Each time you encounter someone trying to claim human-induced global warming is a myth (e.g. because &#8220;Mars is warming too!&#8221;), you can save a lot of time and energy by just saying, oh yes, that&#8217;s myth #16 on the standard list of misunderstandings about climate change. Here&#8217;s the list, lovingly and painstakingly put together by [&hellip;]<\/p>\n","protected":false},"author":392,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,27],"tags":[],"aioseo_notices":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/posts\/925"}],"collection":[{"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/users\/392"}],"replies":[{"embeddable":true,"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/comments?post=925"}],"version-history":[{"count":2,"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/posts\/925\/revisions"}],"predecessor-version":[{"id":1344,"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/posts\/925\/revisions\/1344"}],"wp:attachment":[{"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/media?parent=925"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/categories?post=925"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.easterbrook.ca\/steve\/wp-json\/wp\/v2\/tags?post=925"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}