<story><title>Do climate models predict extreme weather?</title><url>http://backreaction.blogspot.com/2022/01/do-climate-models-predict-extreme.html</url></story><parent_chain><item><author>timmg</author><text>One of the things about &amp;quot;extreme weather attribution&amp;quot; that makes me uncomfortable is the asymmetry of it.  To be clear: I&amp;#x27;m in no way an expert (or even educated) in the area.&lt;p&gt;To give an example.  Let&amp;#x27;s say there&amp;#x27;s a 1% chance every year that there will be a catastrophic wildfire in some particular area.  Now let&amp;#x27;s say climate change increases a chance of drought in that area.  Then we get a wildfire one year and the attribution is (say) &amp;quot;20% due to climate change&amp;quot; -- which I guess means there is now a 1.2% annual chance of a catastrophic fire.&lt;p&gt;But what if climate change causes more rain in the area?  And, for the sake of argument, that causes the change of catastrophic fire to go &lt;i&gt;down&lt;/i&gt; to say 0.8%.  Then, in a given year, there is &lt;i&gt;no&lt;/i&gt; fire.  No one is going to bother doing an attribution study to say, &amp;quot;Climate change is 20% responsible for the fact that we &lt;i&gt;didn&amp;#x27;t&lt;/i&gt; have a fire this year.&amp;quot;</text></item></parent_chain><comment><author>contravariant</author><text>That&amp;#x27;s why in these discussions it&amp;#x27;s usually better to talk about specific statistics like &amp;#x27;the chance of a wildfire has gone up by 20%&amp;#x27;, or perhaps more clearly &amp;#x27;the average time between extreme floods has gone down from once every 100 years to once every 60&amp;#x27; (which I find communicates the point a bit more clearly).&lt;p&gt;That said personally I think that should be as far as the discussion goes, talking about a &lt;i&gt;specific&lt;/i&gt; event and asking whether it&amp;#x27;s because of climate change is silly and leads to counter intuitive results because by nature extreme weather events are &lt;i&gt;mostly&lt;/i&gt; caused by bad luck.&lt;p&gt;Climate changes the &lt;i&gt;frequency&lt;/i&gt; of extreme events, but talking about the frequency of a singular specific event is impossible. And talking about just 1 or 2 of them isn&amp;#x27;t quite enough either, events will occur at a rate &lt;i&gt;far&lt;/i&gt; above or below that predicted by the best weather models simply because of (bad) luck.&lt;p&gt;I sometimes get the feeling that people try to attribute extreme weather to climate change because it improves the narrative, or as proof that climate change has happened. But personally I find this a bit silly since the fact that the global average temperature has increased and the effects this has on weather &lt;i&gt;shouldn&amp;#x27;t&lt;/i&gt; be all that controversial.</text></comment>
<story><title>Do climate models predict extreme weather?</title><url>http://backreaction.blogspot.com/2022/01/do-climate-models-predict-extreme.html</url></story><parent_chain><item><author>timmg</author><text>One of the things about &amp;quot;extreme weather attribution&amp;quot; that makes me uncomfortable is the asymmetry of it.  To be clear: I&amp;#x27;m in no way an expert (or even educated) in the area.&lt;p&gt;To give an example.  Let&amp;#x27;s say there&amp;#x27;s a 1% chance every year that there will be a catastrophic wildfire in some particular area.  Now let&amp;#x27;s say climate change increases a chance of drought in that area.  Then we get a wildfire one year and the attribution is (say) &amp;quot;20% due to climate change&amp;quot; -- which I guess means there is now a 1.2% annual chance of a catastrophic fire.&lt;p&gt;But what if climate change causes more rain in the area?  And, for the sake of argument, that causes the change of catastrophic fire to go &lt;i&gt;down&lt;/i&gt; to say 0.8%.  Then, in a given year, there is &lt;i&gt;no&lt;/i&gt; fire.  No one is going to bother doing an attribution study to say, &amp;quot;Climate change is 20% responsible for the fact that we &lt;i&gt;didn&amp;#x27;t&lt;/i&gt; have a fire this year.&amp;quot;</text></item></parent_chain><comment><author>vkou</author><text>This year, the pacific north west got hit with the four Fs. Fires, floods, and fucking freezing weather.&lt;p&gt;In the summer, we had an unprecedented heat wave which killed thousands of people. Seattle hit 108°F&amp;#x2F;42°C. The town of Lytton, BC, hit 118°F&amp;#x2F;48°C[0], &lt;i&gt;and then completely burnt down in a 30 minute firestorm&lt;/i&gt;. More rain would have been great.&lt;p&gt;We didn&amp;#x27;t get it.&lt;p&gt;We got it in the winter, and it was absolutely devastating. [1] To cap the year off, we ended with a record-setting freeze (With, thankfully, comparatively moderate snowfalls).&lt;p&gt;So, yes, more rain, less rain, more heat, less heat, we got all that. Unfortunately, weather is not a bank account, and having your town burn down to the ground in the summer, followed by a flood in the winter doesn&amp;#x27;t tend to cancel things out.&lt;p&gt;[0] An all-time heat record for Canada.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;November_2021_Pacific_Northwest_floods&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;November_2021_Pacific_Northwes...&lt;/a&gt;</text></comment>