PowerSwitch

When does weather become climate? The Meterological Office uses 30 year ranges in order to create averages with which to compare current weather.
The recent warming cycle started (arguably) in 1988 and more or less had run its course by the early 2000s. In the last 10 years temps have been approximately level, despite CO2 levels continuing to increase annually.

In my little corner of the world we have had 5 poor summers in a row now. By poor, I mean few sunny, warm periods (more than 2 or 3 days) in the summer months of June, July August. This year temps have rarely risen above 21c (70f in old money) and we have had lots of cloud and rain with many days maxing out at 15 or 16c and some days having a max of 13c or 14c, although we do get this a couple of days most summers. I joke that we have days in July as cool as mild Boxing Days where I have recorded maxes of 13c! (I really should move to the South of England shouldn't I. )

Meanwhile we have had 3 cool winters on the trot, with winter 2009/10 going right thru to May and a very late spring, confirmed by gardners in National Trust Parks. And of course the unforgetable December 2010 which was the coldest in Ireland since records began. I recorded -16c in my back garden on 3 or 4 nights and recall very clearly seeing a temperature of -12c at 1300 GMT in my car in Hillsborough, a few days before Christmas. We had snow on the trees (picture postcard style) for many days as the temp never rose above 0c even in the sunshine.

Just wanted to lay these thoughts out, as it doesn't seem to tally with rising global temps in my tiny corner of our planet.

PS. With the solar cycle so low at the moment, I guess there is a good chance of having a colder than average winter this year, or at least some very significant cold periods. Time will tell.

snow hope wrote:
In my little corner of the world we have had 5 poor summers in a row now. By poor, I mean few sunny, warm periods (more than 2 or 3 days) in the summer months of June, July August. This year temps have rarely risen above 21c (70f in old money) and we have had lots of cloud and rain with many days maxing out at 15 or 16c and some days having a max of 13c or 14c, although we do get this a couple of days most summers. I joke that we have days in July as cool as mild Boxing Days where I have recorded maxes of 13c! (I really should move to the South of England shouldn't I. )

Sure, if you fancy the risk of drought.

I'd swap your weather for mine anyday, but I have vested interests in rain.

11 year sunspot cycle, innit....

Roll on 2014....I'd almost be willing to make a bet

Careful . .

http://www.realclimate.org/index.php/ar ... d-minimum/

...which is why I said "almost"

snow hope wrote:When does weather become climate?

The simple answer is that climate is weather averaged over a period of time. A slightly more complex answer is necessarily a bit longer, so I've posted it here.

Another definition would be that what we experience as weather is distribution of solar energy within our atmosphere. Weather doesn't just happen, it is driven by temperature differences and the effects of water vapour.

Climate however is the propensity for a given weather to happen at a given place. It rains a lot in Ireland and over long period we could arrive at a set of normal bounds for the number of rainy days and how much rain fell. We would expect variation within the bounds and we could note extreme events but we could be fairly sure of their probability. Similarly the Sahara is generally sunny and we could establish similar data for the weather there.

Change in climate is therefore a shift in the boundaries of established norms for weather. Once upon a time rain fell reliably on the Sahara and it supported life. That is no longer the case so we can justifiably say the climate wrt to the Sahara has changed.

The thing is that we know that our climate has been constantly changing for ever. It can spend ages reasonably static and then flip over to or from an Ice Age on a decadal scale.

So when do we know that changes in weather are indicative of changes in climate? Simply put we have to wait for enough data to show that we have to establish new norms for our weather.

You can also see the problem with talking about a 'global climate'. It has such a massive scope that it is mostly meaningless. We know the bounds of all the normal measurements for many places but trying to aggregate the weather data of the Andes with that for London is kinda pointless. Data showing a consistent long term shift in the upper temperature bound (for instance) at all locations would be a very reliable indicator of a global warming trend. Having a couple of sunny Summers in 2006 wouldn't be.

What you cannot have is anything claiming to influence climate that does not show up in weather data.

On the plus side, this weather is making the bamboo in my garden grow quite well.

Just as we are confident that gravity will pull the mountain waters down to the sea, however circuitously, we are confident that the anthropogenic greenhouse gases will shift global temperatures higher. But climate is a chaotic system. Expect eddies, expect meanders. Don’t assume that tomorrow will be warmer than today; that next year will be warmer than this. But do be assured that this century will be warmer than last. The influence of the greenhouse gasses on global warming is certain as gravity on a river.

Nice blog Biff.

We can't see climate from our personal time scale, but it happens.

Ta.

snow hope wrote:When does weather become climate? The Meterological Office uses 30 year ranges in order to create averages with which to compare current weather.
The recent warming cycle started (arguably) in 1988 and more or less had run its course by the early 2000s. In the last 10 years temps have been approximately level, despite CO2 levels continuing to increase annually.

In my little corner of the world we have had 5 poor summers in a row now. By poor, I mean few sunny, warm periods (more than 2 or 3 days) in the summer months of June, July August. This year temps have rarely risen above 21c (70f in old money) and we have had lots of cloud and rain with many days maxing out at 15 or 16c and some days having a max of 13c or 14c, although we do get this a couple of days most summers. I joke that we have days in July as cool as mild Boxing Days where I have recorded maxes of 13c! (I really should move to the South of England shouldn't I. )

Meanwhile we have had 3 cool winters on the trot, with winter 2009/10 going right thru to May and a very late spring, confirmed by gardners in National Trust Parks. And of course the unforgetable December 2010 which was the coldest in Ireland since records began. I recorded -16c in my back garden on 3 or 4 nights and recall very clearly seeing a temperature of -12c at 1300 GMT in my car in Hillsborough, a few days before Christmas. We had snow on the trees (picture postcard style) for many days as the temp never rose above 0c even in the sunshine.

Just wanted to lay these thoughts out, as it doesn't seem to tally with rising global temps in my tiny corner of our planet.

PS. With the solar cycle so low at the moment, I guess there is a good chance of having a colder than average winter this year, or at least some very significant cold periods. Time will tell.

Global "warming" is a misleading term to the layman. It refers to mean average global temperature. This has indeed been rising. However, in localised terms it can mean that temperature can flutuate eather way. For example, the North Atlantic Conveyor Belt could concievably turn off as a result of global warming. This would mean, for the UK, that temperatueres could plummet.

Essentially, the atmosphere is soaking up more of the sun's energy than it did previously, resulting in a more energetic climate. A more energetic climate means, at the global level, temperature does indeed rise. However, at the local level it means that you just get more extreme weather events. Sometimes very hot, sometimes very cold, sometimes very wet, sometimes very dry, sometimes very windy etc...

Well said, Steve. That extra energy in the system flows around and causes unpredictable weather events.
Jon

stevecook172001 wrote:Global "warming" is a misleading term to the layman. It refers to mean average global temperature. This has indeed been rising. However, in localised terms it can mean that temperature can flutuate eather way. For example, the North Atlantic Conveyor Belt could concievably turn off as a result of global warming. This would mean, for the UK, that temperatueres could plummet.

That's why I'd rather use the term 'climate change'.

The trouble with 'global warming' is that it suggests that the globe is warming. Which it is. And many folk really don't want to know that.

Climate change is just the same old same old.

However, another problem is that 'global warming' suggests everywhere will warm (which we know may not be true). But as Joe Bloggs in the UK actually wants the climate to warm this isn't a problem - you should hear the people I work with talk about it.