Sunday, March 09, 2008

More Non Consensus

Only about one in three Alberta earth scientists and engineers believe the culprit behind climate change has been identified, a new poll reported today.

The expert jury is divided, with 26 per cent attributing global warming to human activity like burning fossil fuels and 27 per cent blaming other causes such as volcanoes, sunspots, earth crust movements and natural evolution of the planet.

A 99-per-cent majority believes the climate is changing. But 45 per cent blame both human and natural influences, and 68 per cent disagree with the popular statement that "the debate on the scientific causes of recent climate change is settled."


Anonymous said...

I remain open minded about your conclusions on night time temperatures
The issues the BOM have - as per Blair Trewin are several but the two main ones are: 1 - you cant exclude the confounding influence of daylight saving which will keep night temps lower since it was introduced
2 - you are using data from stations with too short a record.
When you assess any given station - do you use the same period for the max and min as the timed data or do you use the much longer periods of record for the max and min which are showing significant trends but a shorter time for the time based data.
Blair Trewin certainly replies to my queries about your work very promptly and I do wonder why you havent't shown them your results if you believe it to be true

Jonathan Lowe said...

1 - the issue of daylight savings is an interesting one. If I were comparing temperatures in Brisbane at 9am to temperatures in Melbourne at 9am in summer, then this would be an issue.

It would also be an issue if I were comparing temperatures at 9am in Melbourne in Jan. to temperatures at 9am in Melbourne in June.

However, neither of these are the case. My analysis compares temperatures of Melbourne at 9am in june in one year to temperatures of Melbourne at 9am in another year during the same monthly only. All differences therefore are relative.

2 - What is to short a record? Most stations analysed here with time based temperature readings go back to the mid 1940s (63 years). The BoM use temperatures going back to 1910 for their analysis, so a bit longer. Either way, the strong positive trend from 1945 to now is obvious and should still occur in time based temperature analysis.

Jonathan Lowe said...

I'd be interested in Blair Trewin's commens of my work. The reason why I haven't pushed this analyis further is for a number of different personal reasons.

1 - Traveling, which I will be doing extensively in the next year (so perhaps limited blog updates :( )
2 - Work. Work is going great and really busy, so time for temperature analysis is limited.

But I do intend to take the analysis further.

Anonymous said...

Daylight saving cannot possibly have an effect on nighttime temps, or daytime temps for that matter.

What it may effect is temps at a particular time of day. However, I would assume the BoM is smart enough to use non-daylight saving times in their record keeping.

Point 2 is poorly phrased, but what I think is meant is, are you comparing time of day data and min-max over the same time period?

Otherwise, I don't see why jonathan needs to show his work to the BoM. If they interested, they can come and ask him or do their own analysis; It's their data. If they have something to say, they should say it.

This isn't the Soviet Union where the government has to approve everything that is said publicly.


Jonathan Lowe said...

unfort. the BOM are not smart enough to use non-daylight savings times in their record keeping.

Anonymous said...

Unbelievable. Especially as this obvious practice was how they used to collect temperature data.