Heads I Win, Tails You Lose!
By Paul Homewood
You will doubtlessly recall the BBC story a couple of weeks ago, about research suggesting that transatlantic flight times would significantly lengthen because of global warming.
The author of the study, Dr Paul Williams was quoted as saying:
We know what drives the jet stream, it’s the temperature difference between the warm tropical regions and the cold polar regions at flight levels.
We understand what that temperature difference is going to do in response to global warming, it’s increasing, we are very confident that the jet stream is increasing as a consequence.
As I pointed out at the time, the opposite is happening, the temperature difference is falling, not increasing.
Booker also picked on my story, and made similar comments. Piqued by being outed as a charlatan, Williams penned this letter to the Sunday Telegraph last week:
However, as my original post showed, the temperature difference is decreasing in the atmosphere, and not increasing, at the levels where aircraft fly, as he claims.
So, to repeat:
First, the Mid Troposphere, which runs from about 2 miles to 6 miles up, just the region where the jet stream runs and the aircraft fly. (According to the Met Office, the polar jet stream is typically between 5 and 7 miles up). This is from RSS:
And we see just what we expected, that the Northern Polar region has warmed up much more.
And, just for good measure, the Lower Troposphere, up to 2 miles:
Exactly the same.
Even when we go up to the lower stratosphere, we find exactly the same thing. Temperatures above the North Pole are not falling as quickly as lower latitudes, ie the differential is falling.
Below is the RSS chart showing the various heights involved.
But please don’t just take it from me, see what Arctic climatologist, De Jennifer Francis, had to say about the jet stream last year:
The Arctic has warmed at approximately twice the rate of the Northern mid-latitudes since the 1990s owing to a variety of positive feedbacks that amplify greenhouse-gas-induced global warming. This disproportionate temperature rise is expected to influence the large-scale circulation, perhaps with far-reaching effects. The North/South temperature gradient is an important driver of the polar jet stream, thus as rapid Arctic warming continues, one anticipated effect is a slowing of upper-level zonal winds. It has been hypothesized that these weakened winds would cause the path of the jet stream to become more meandering, leading to slower Eastward progression of ridges and troughs, which increases the likelihood of persistent weather patterns and, consequently, extreme events . While weaker zonal winds have been observed in response to reduced poleward temperature gradients, the link to a wavier upper-level flow has not yet been confirmed , although recent studies provide strong support of a mechanism linking sea-ice loss in the Barents/Kara Sea with amplified patterns over Eurasia during winter and summer .
This whole saga rather sums up the state of climate science nowadays. You simply make things up to suit whatever your objectives are.
For Francis, it was to link extreme weather to global warming. For Williams, it is to convince us that we will end up paying more for our air fares.
Just read again Williams’ final sentence:
But its impact on aviation is only just being explored.
Translation, we need a lot more money to investigate.
The whole thing stinks.