Tuesday, 17 November 2009

10°C at 6.00am in mid November!

Oh no the safari has been messing with figures and statistics...

That is a very balmy (or should that be barmy) temperature for the time of year.
Is this ‘normal’ or is it a sign of climate change? A ‘normal’ expected ‘average’ temperature for that time of day at this time of year would be 4°C – so certainly some difference there!
We have been keeping a beady eye on the daily temperatures here in Blackpool since the turn of the Millennium and have started to notice some trends. The weather station we use is at the airport and has been operational for many years with Met Office records dating back to before 1961. Although it has been operational for all that time it is not an ‘official’ National Weather Station and does not contribute to the Central England Temperature (CET) records. This is a triangular area through the, obviously, centre of the country with its apices at Preston, Bristol and London.
The airport weather station is far enough out of town to be unaffected by the residual heat from the built up area but is near enough to accurately reflect the conditions experienced locally.
The graph below has two components; the upper three lines represent the daily maximum temperatures and the bottom three lines the daily minimum temperatures, usually but not exclusively night time temperatures.
The two ‘paired’ lines give the values for the two thirty year periods, 1961 – 1990 and 1971 – 2000 and show that there was little difference in either the maximum or minimum daily temperatures between.
We are now getting towards the end of the current thirty year period 1981 – 2010. How will it compare with the previous two?
So what do our records show?
Instantly noticeable is the brown line that is clearly above the lowest pair of lines. This tells us that the average daily minimum temperature is now significantly warmer than in previous years.
The yellow line shows a slight increase in maximum daily temperatures during the spring and early part of the summer, the rest of the year being pretty much as expected.
Strange goings on then…and not particularly easy to understand. If the current increase in the concentrations of greenhouse gases in the atmosphere are causing climate change you would be excused for thinking that they would work during the day as well as at night. I have no rational explanation for the observed difference…can any wise and knowledgeable person shed some light on our mis-matched phenomenon? It’s not only us there has been an observed shrinking of the max-min temperature differential from many places around the world.
Now it is important to understand that you shouldn’t really make direct comparisons of only nearly ten years of data with a thirty year sequence. Unfortunately I don’t have access to the information to be able to go back to 1981. When the official figures are released in early 2011 we’ll be able to see how much change there has been between the three thirty year periods. The next set of data, 1991 – 2020 will be even more interesting as it takes us beyond the 1961 – 1990 data. I wonder what it will show…can’t wait! But if it warms up enough to secure Cetti’s Warblers as a breeding species I’ll be a happy bunny. What if we get temperatures more akin to Benidorm than Blackpool? What might we expect to colonise then? Over the last 10 -15 years we’ve already seen the northward march of Migrant Hawker and Ruddy Darter dragonflies, Large and Small Skipper butterflies – it’ll take a very observant and/or lucky person to pull out our first Essex Skipper when they get this far north. I say ‘when’ because I think it’s much more likely than if. I’m looking out for our first Marbled White – a really bonny looking butterfly. If these are all winners, which species will the losers? It’s really hard to be able to make a prediction. Some of those currently declining ‘seem’ to be doing so for reasons more akin to negative habitat changes, such as the oft cited farmland birds. So who knows? All we can say with any certainty is that there is change afoot, probably quite a lot of change in the coming decade or two, and we need to monitor our wildlife carefully so that climate change, which in the short term at least we are probably not going to be able to control, is not used as an excuse for a particular species, or suite of species, not doing so well when poor habitat ‘management’, which we do have some control over, is actually the cause.
As for sea-level rise – 170mm (7”) in the last 100 years preceded by about the same in the previous 2000 years - how much will we get and when is very much open to debate and possibly more closely linked to post-glacial isostatic adjustment (rebound) than increasing temperatures. It’s still gonna go up though whichever mechanism is in control. A metre by 2100 – I like to live long enough to see that! It’ll make quite a mess. Where’s me boat?
For all you climate sceptics out there surely it’s best not to add to the GG load in the atmosphere just in case…or you can go on polluting and hope the IPCC etc have got it wrong as you suggest. One thing I think will happen is that humans will use every last drop of oil, wisp of natural gas and lump of coal…how fast we do that will have a bearing on our future, do it quick without a care in the world and we’ll make a rod for our own back, but slow down and let the technologists find solutions and we’ll do OK. With big bucks and big greed in charge the former is more likely than the latter.
Essay over- - where on earth did that little lot come from?
Where to next? I’ll bet you’re hoping we get out on safari and see some wildlife SOON…some mammals would be nice.
In the meantime let us know how far up the pier legs the sea is rising in your outback.

No comments: