Tuesday, January 07, 2020

Weather and Climate


Interesting historical data on weather events on the met-check web site, you can type in your postcode and see the most likely (statistically) first and heaviest snow dates where you live. For me the heaviest is most likely around the 25th of February, which is quite late in the Winter but even anecdotally, from past experience, feels about right. Of course weather isn't the same as climate, whilst there may well be extreme weather events from time to time, like a heavy downpour of snow, climate is much more about the averages over much longer periods of time. It's a common misconception among non-science types that just because it snowed heavily yesterday that global warming must be a hoax, there are many comical examples of this fallacy (by a senior US politician in this case) on the inter-webs. To scientifically literate people these examples are of course laughable but it's scary to know that there are people in real positions of power and influence out there that think this way.

It's been shown, beyond reasonable doubt, that the climate is warming, it's also been shown (historically via ice cores, and, theoretically via climate models) that high levels of Carbon Dioxide and other greenhouse gases cause the average (over time) atmospheric temperatures to rise. The amount of greenhouse gases created by the burning of fossil fuels in the last 500 years by humans has created appropriate levels to raise temperatures noticeably, i.e. it's most likely that we're causing it or at least contributing significantly.  Regardless of culpability, the expected effect of all this extra gas in our atmosphere will be temperature rises (on average) of around 2 centigrade in the next 30 years, which doesn't sound a lot but it's important to understand that this doesn't mean a 2 degree rise in local temperature uniformly across the globe, its does mean that the probability of extremes increases and on average will be more extreme. For example warmest months will be warmer by more than 2 degrees and colder months may well experience colder or more extreme storms. Overall we will see dramatic impacts on our climate (i.e. the character of the average weather as it's distributed over the globe) We will likely see London experiencing Barcelona levels of heat (and drought) in the Summer, which sounds like it might be a good thing, unless of course you suffer from asthma or have a house built on London clay which gets brittle when too dry. The impact on cities further South will be even harsher, drought and crop failure becoming much more common.

The issues with average temperature rises will potentially be dwarfed by the issues caused by melting arctic ice. This will causing sea levels to rise significantly and therefore cities located on low lying land next to the sea could literally be swamped and may have to be largely abandoned. Not great news for many valued national assets, such as London and New York for example. Sadly I think that this is one of those problems that will only be solved bottom-up, i.e. from individual action driving state-action, our politicians seem not to have the courage to do much more than pay lip-service to it.

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