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<div class="moz-cite-prefix">On 24/01/2013 05:26, spike wrote:<br>
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<p class="MsoNormal">A thought occurred to me today as I was
reading about a deep lingering cold snap in upstate New York.
We discuss the notion of global warming, which is based on an
average temperature over the year. But the thermometers are
not evenly distributed. They are generally more concentrated
near population centers. But it is entirely likely that the
concentration factor is insufficient: the distribution of
thermometers should be proportioned according to the local
human population.</p>
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<br>
The unequal distribution of temperature stations in time and space
is a big headache for climate modelling. You need to be very careful
in interpreting measurements because of it. I had great fun playing
around with the Met office climate data a few years back:<br>
<a class="moz-txt-link-freetext" href="http://www.aleph.se/andart/archives/2009/12/digging_into_data.html">http://www.aleph.se/andart/archives/2009/12/digging_into_data.html</a><br>
<a class="moz-txt-link-freetext" href="http://www.aleph.se/andart/archives/2009/12/significant_anomalies.html">http://www.aleph.se/andart/archives/2009/12/significant_anomalies.html</a><br>
The concentration near population centres also means the urban heat
island effect must be controlled for, both in time and space - the
extra thermometers do not necessarily contribute quality data. It is
hard and tricky work. <br>
<br>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> It just doesn’t seem fair somehow. More
people should equal more data in the global average
temperature.<o:p></o:p></p>
<p class="MsoNormal"><o:p><br>
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<br>
No, it should mean more weight in evaluating how good or bad it was.
Multiply the local change with population density and you get a
better measure. <br>
<br>
Suppose all global warming happened in Topeka, Kansas. About 127,000
people would be affected, but the rest of the world would be fine
(and the topekans could move from their boiling city): it would
essentially be no difference. The big temperature increases in the
far north right now are not so bad for humans since nearly nobody
lives above the polar circle - if their effects remained local they
would only be a concern in regards to local ecosystems and economic
exploitability. However, the feedback effects are worth watching for
- they are not well understood yet, but potentially important for
weather and climate patterns across the industrialized - and densely
populated - north. And anything that messes up the Monsoons is Bad
News.<br>
<br>
Generally, scaling importance with population affected seems to be a
good heuristic for setting priorities. <br>
<pre class="moz-signature" cols="72">--
Anders Sandberg,
Future of Humanity Institute
Oxford Martin School
Faculty of Philosophy
Oxford University </pre>
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