In The News

[Thundery wintry showers]

We might expect events like the Boscastle flood to become more frequent with AGW, but there is no compelling evidence that Boscastle had anything to do with AGW, for there has been no obvious increase in the incidence of such events in south-west England. One of Philip Eden's articles pointed out that we were actually well overdue an event of that sort of magnitude in SW England, with such events having been more common earlier in the 20th century than later in the century.

[pottyprof]

I do appreciate an unwillingness to accept our 'forcing' of climate but ,year in ,year out, we see measurable evidence of our impacts.

But it's not an unwillingness to accept. It's a case of looking back in history to see these events will and do happen in the natural running of things. It's one reason why sometimes I sit here shaking my head at some of the bunkum that gets posted on a lot of the climate sites. There is no evidence that these events are caused by AGW. I posted the piece about the Nile as this is the one river where there are records that date back several thousand years.

As for Boscastle... I think you are confusing weather and climate. There has always been extremes and always will be.

[Devonian]

But it's not an unwillingness to accept. It's a case of looking back in history to see these events will and do happen in the natural running of things. It's one reason why sometimes I sit here shaking my head at some of the bunkum that gets posted on a lot of the climate sites. There is no evidence that these events are caused by AGW. I posted the piece about the Nile as this is the one river where there are records that date back several thousand years.

As for Boscastle... I think you are confusing weather and climate. There has always been extremes and always will be.

If the UK climate warms by 2C it seems reasonable to think there may well still be convergence type storms over the Boscastle area - the geography wont have changed. Indeed I don't see why they might not happen if we see 4C warming. Would that mean they're caused by AGW? I think that would clearly the wrong question to ask since Boscastle type storms are caused by a combination of effects.

Would AGW be one of the effects? Clearly it would.

[pottyprof]

If the UK climate warms by 2C it seems reasonable to think there may well still be convergence type storms over the Boscastle area - the geography wont have changed. Indeed I don't see why they might not happen if we see 4C warming. Would that mean they're caused by AGW? I think that would clearly the wrong question to ask since Boscastle type storms are caused by a combination of effects.

Would AGW be one of the effects? Clearly it would.

We could also look at the flooding that occurred around here a few years back. With the media coverage, it would be seen by many as a new occurrence. The thing is, it isn't. Even before the turn of the 19th century, there are records that detail flooding. Is that down to a 2c or 4c rise in temperatures?? Nope!!

[Thundery wintry showers]

Unless there is evidence of an increase in the frequency of events above a certain magnitude we cannot reasonably say that AGW is causing increased extreme events. There isn't much evidence (yet) for an increase in extreme events in SW England.

But if, over the coming decades, we see a notable increase in the frequency of extreme events in SW England, and at the same time global temperatures keep on rising, then we will be more justified in pointing a finger at AGW.

[pottyprof]

But if, over the coming decades, we see a notable increase in the frequency of extreme events in SW England, and at the same time global temperatures keep on rising, then we will be more justified in pointing a finger at AGW.

That, I completely agree with.

[Devonian]

We could also look at the flooding that occurred around here a few years back. With the media coverage, it would be seen by many as a new occurrence. The thing is, it isn't. Even before the turn of the 19th century, there are records that detail flooding. Is that down to a 2c or 4c rise in temperatures?? Nope!!

Right, but I'm not saying it's the only reason. I just think AGW is an increasing part of the climate and thus weather mix. It might not be obvious, it might never be with phenomena like Boscastle storms, but it is and will increasingly be one of the ingredients.

As ever it comes beck not to if AGW exists - it does - but it's magnitude now and in the future.

I agree with TWS.

Edited October 5, 2010 by Devonian

[pottyprof]

As ever it comes beck not to if AGW exists - it does - but it's magnitude now and in the future.

I agree with you on that Dev. My point though, originally, was that some people blame AGW on all extreme events. This is not the case. The SW has always been prone to extreme events just purely by it's exposed position. I'm not sure how anyone would be able to differentiate between a "natural" event or an "AGW forced" event.

One thing is for sure though. News travels fast and we are now able to document things far more accurately. This may just give the impression that these things are happening with increased frequency?

[Thundery wintry showers]

I think the evidence for more extremes of precipitation in the UK is quite mixed- many of the trends that we saw during the 1980s and 1990s have reversed during the 2000s. But temperature wise we have definitely moved towards more warm extremes.

[weather eater]

Right, but I'm not saying it's the only reason. I just think AGW is an increasing part of the climate and thus weather mix. It might not be obvious, it might never be with phenomena like Boscastle storms, but it is and will increasingly be one of the ingredients.

As ever it comes beck not to if AGW exists - it does - but it's magnitude now and in the future.

So, I agree with TWS.

We could look at the question in several ways.

Q. Is it possible that AGW had a part to play in the Boscastle flood.

A. Yes its possible given what we know about a warming climate and rainfall.

Q. Is there any quantifiable evidence that AGW played a part.

A. No.

Q. Is there any quantifiable evidence that these types of events are becoming more common or more intense in the UK.

A. No, there is no study, at least to the best of my knowledge that proves this. The historical record has many instances of instance rainfall of a similar magnitude.

Q. Is human activity, in terms of altering the structure of the land, making it appear that these types of weather events are becoming more intense.

A. Yes, a good example is the Lynmouth flood of 1952 where the culverting of the river Lyn through the town center exacerbated the flood by acting as a bottle neck.

[knocker]

Contrary to media reports, serious flooding has occurred before at Boscastle: in late-October 1996 when ex-hurricane Lili delivered a combination of heavy rain and high tides that inundated the lower part of the village; in the Junes of both 1958 and 1957 when sudden floods developed in circumstances similar to last Monday; and in July 1847 when a much broader region was affected.

http://www.weatheronline.co.uk/reports/philip-eden/Some-facts-and-figures.htm

By coincidence in this months Geographical magazine.

Extreme weather events are becoming both more frequent and more severe, causing profound problems for the developing world. Some scientists believe that these disasters are the result of man-made climate change, but can a link be proven? Mark Rowe investigates

[knocker]

Further to the debate.

What Role Might Climate Change Have Played in the Recent East Coast Deluge?

The heavy rains that inundated the East Coast during the last week of September were the result of a rare combination of ingredients — namely a wide-open, 3,000-mile-long pipeline of tropical moisture extending from the Caribbean all the way up to Maine and the Canadian Maritimes, a stalled frontal boundary, and multiple waves of low pressure that rode along that boundary. Many cities set new single and multiday rainfall records, and the rain led to severe flash flooding from North Carolina to New York State.

http://theenergycollective.com/andrewfreedman1/44570/what-role-might-climate-change-have-played-recent-east-coast-deluge

[pottyprof]

But temperature wise we have definitely moved towards more warm extremes.

But it depends on what you mean by warm extremes. Yes, it's been an interesting couple of decades where we have had record high temperatures but have these sorts of temperatures been reached before and not recorded? It is possible because the temperatures we have seen are not out of reach or unusual given the right conditions.

These were my first thoughts from your comment..........

This to me is where the media fail with their attempts to get people to understand what is happening.

Headline news should be.. Night time minimum temperatures are at record highs.. Now with that added to your comment, I totally agree and that for me tips the balance....

Edit...

That isn't to say I believe that it's all AGW.. It could be a process we don't understand as yet or the oceans giving up heat into the atmosphere. Or it could just be the obvious??

[Guest mycroft]

I think the evidence for more extremes of precipitation in the UK is quite mixed- many of the trends that we saw during the 1980s and 1990s have reversed during the 2000s. But temperature wise we have definitely moved towards more warm extremes.

And we have had two strong el ninos in 12 years,PDO has gone negative so le ninas should be stronger in coming decades. Lets see if there is correlation in global temps

[Thundery wintry showers]

Hmm... would you be saying the same if we'd gone through a period of stable global temperatures or a slight cooling, assisted by two strong La Ninas, and were looking at the modes of natural variability switching to positive?

Global temperatures have stayed above the long-term average in the last decade even when we've had La Ninas so ENSO cannot account for a large proportion of the warming, although the bias towards a positive state in the 80s and 90s probably contributed one or two tenths of a degree.

[pottyprof]

What more can I say?

http://www.thedailymash.co.uk/news/environment/trees-will-not-become-unstoppable-killing-machines,-admit-climate-scientists-201002022433/

[jethro]

What more can I say?

http://www.thedailym...s-201002022433/

Oh thank you Potty, just what I needed

[Gray-Wolf]

Tree-mendous in fact!.......

EDIT: The heat goes on........

http://climateprogress.org/2010/10/04/endless-summer-hottest-september-record-high-temperatures/

Edited October 6, 2010 by Gray-Wolf

[Guest mycroft]

Hmm... would you be saying the same if we'd gone through a period of stable global temperatures or a slight cooling, assisted by two strong La Ninas, and were looking at the modes of natural variability switching to positive?

Global temperatures have stayed above the long-term average in the last decade even when we've had La Ninas so ENSO cannot account for a large proportion of the warming, although the bias towards a positive state in the 80s and 90s probably contributed one or two tenths of a degree.

YES, I am suggesting that with a negative PDO and strong la ninas coming up maybe the temps bias will swing the other way?

[Guest mycroft]

Tree-mendous in fact!.......

EDIT: The heat goes on........

http://climateprogress.org/2010/10/04/endless-summer-hottest-september-record-high-temperatures/

The fat lady has not sung yet GW...she may yet be asked back to perform with the rest of her en semble,though i suspect members 15,16,17,18, will be retired due to not performing up to scratch

http://www.oso.noaa.gov/poesstatus/spacecraftStatusSummary.asp?spacecraft=15

[knocker]

Madan Shrestha of the Nepal Academy of Science and Technology remarks, "We have ample scientific evidence to prove that climate change is causing the Himalayan glaciers to retreat." Don't tell the IPCC.

http://ipsnews.net/news.asp?idnews=53044

Freshwater is flowing into Earth's oceans in greater amounts every year, a team of researchers has found, thanks to more frequent and extreme storms linked to global warming.

http://www.sciencedaily.com/releases/2010/10/101004151700.htm

And a new definition for "extracting the urine".

http://www.bbc.co.uk/news/science-environment-11468145

[Coast]

Declining solar activity linked to recent warming

The Sun may have caused as much warming as carbon dioxide over three years

www.nature.com/news

www.independent.co.uk/environment/climate-change

[laserguy]

www.nature.com/news

www.independent.co.uk/environment/climate-change

That's it then,we've had it. The sun has it in for us,whether it's global warming due to increased activity / global warming due to decreased activity / ice age II 'because of no sunspots / solar flares taking us all out in 2012 etc. I can't take it anymore!

[SteveB]

Slightly different take on the same story in the Daily Mail

http://www.dailymail.co.uk/sciencetech/article-1318425/Global-warming-theory-chaos-Increased-solar-activity-COOL-Earth.html

[knocker]

Going.........And Almost Gone.

Two of the approximately 26 remaining glaciers (under snowfield) at Glacier National Park, MT, June 19, 2010. In 1850, the park had an estimated 150 glaciers; all glaciers expected to be gone by year 2030.

Courtesy U.S. Geological Survey/photo by Connie Loper.

Edited October 7, 2010 by weather ship