'Man-made' global warming

UPDATE: Make that FOUR interesting articles today: Watts Up reports that a new paper attributes half the global warming signal in the last century to “data homogenisation” – that’s plain old fudging to you and me. And in 2/3 of the stations, the process resulted in a temperature increase. What a surprise! Not. Read it all.

I am as prepared as anyone to accept that we are causing some warming of the climate. However, the precise amount and whether it’s a problem is the key issue.

The surface temperature data sets all show a fairly marked recent warming (far more than the satellite record), but how much of that warming is due to changes in the climate, and how much is due to, say, urbanisation, or data “homogenisation”? Homogenisation is a polite way of saying “fudging”, by the way. Excuses to “adjust” raw data for a variety of reasons, some legit, some less so – changing instrumentation, location etc etc.

Despite the fact that you would expect surface temperatures to have generally increased with population and urbanisation, and therefore any adjustments should cool the more recent records to compensate, the bizarre thing is that the data sets appear to be “cooling the past”, to make the present appear warmer… huh?

Three interesting articles today from various blogs concern the surface temperature record. Firstly we have Steven Goddard on the US Historical Climate Network (USHCN):

The animation below shows how USHCN turns a measured strong cooling trend since 1930, into a strong computer generated warming trend.

USHCN2 uses a three step process to cool the past and warm the present. Going from the actual measured daily data to “raw monthly” reduces the decline. The TOBS adjustment flips the trend from cooling to warming, and then a final mysterious adjustment creates a strong warming trend.

Whatever the final mysterious adjustment is, it has to include UHI – which would do the exact opposite of what we are seeing.

(click to see animation)

Watch those older temperatures plummet inside Tom Karl and James Hansen’s computer games, which are used to influence critical US government policy decisions.

They cool the 1930s by 1.3 degrees, and then claim that the past decade has been the warmest by a few tenths of a degree. Enron accountants would be proud of such fine data presentation. (source)

See? Man-made global warming! Then we have Jo Nova on the Bureau of Meteorology, which hasn’t yet worked out a rather fundamental rule of temperature recording:

In total, the ACORN-SAT database released in March displays about 1,000 (one thousand) violations of [the] simple rule that for any day

The Maximum Temperature must be greater than the Minimum Temperature.

This is a blindingly obvious type of error which should not have escaped quality control. It throws serious doubt on the whole ACORN-SAT project. In my opinion, these violations indicate that the entire ACORN-SAT database is suspect, and should be withdrawn for further testing. (source)

Hmm. And finally, over the ditch in New Zealand, the National Institute for Atmospheric and Water Research (NIWA) is in court today faced with a challenge that its temperature record is also not so ‘hot’ (heh):

A climate change group has taken the National Institute for Atmospheric and Water Research (NIWA) to court over what they say are inaccurate temperature recordings.

The New Zealand Climate Education Trust – a branch of the NZ Climate Science Coalition – are challenging NIWA figures which show a rise in temperatures in New Zealand of 1degC over the past 100 years.

This figure is significantly higher than global warming figures around the world and the trust is questioning how NIWA calculated the figures and whether they are accurate.

It believes there has either been no warming or a trivial warming of around 0.2degC.

The group’s lawyer Terry Sissons told the High Court at Auckland today that  NIWA could have obtained inaccurate New Zealand average temperatures due to ‘sudden site relocations’ and by regularly changing temperature gauging instruments.

“We’re not saying that climatic changes are not happening but let’s at least ensure the evidence gathered for the benefit of New Zealanders is accurate and is done properly,” Sissons said. (source)

So in other words I think we have a ‘consensus’, ladies and gentlemen: surface temperature records are a crock the world over.

Ice core data shows Greenland warmer in the past

Greenland temperatures (click to enlarge)

It appears that in Greenland at least, the current warming cannot be said to be “unprecedented”, since similar magnitudes and rates of warming are present in several previous eras. Man certainly didn’t cause those warming periods, so natural climate change obviously had a significant effect on Greenland temperatures over the past 4000 years.

In a paper entitled “High variability of Greenland surface temperature over the past 4000 years estimated from trapped air in an ice core” the authors state:

… we reconstruct Greenland surface snow temperature variability over the past 4000 years at the GISP2 site (near the Summit of the Greenland ice sheet; hereafter referred to as Greenland temperature) with a new method that utilises argon and nitrogen isotopic ratios from occluded air bubbles. The estimated average Greenland snow temperature over the past 4000 years was −30.7°C with a standard deviation of 1.0°C and exhibited a long-term decrease of roughly 1.5°C, which is consistent with earlier studies. The current decadal average surface temperature (2001–2010) at the GISP2 site is −29.9°C. The record indicates that warmer temperatures were the norm in the earlier part of the past 4000 years, including century-long intervals nearly 1°C warmer than the present decade (2001–2010). Therefore, we conclude that the current decadal mean temperature in Greenland has not exceeded the envelope of natural variability over the past 4000 years, a period that seems to include part of the Holocene Thermal Maximum. 

However, in order to get it past the pal-review system, the following caveat was inserted to appease the headbangers:

Notwithstanding this conclusion, climate models project that if anthropogenic greenhouse gas emissions continue, the Greenland temperature would exceed the natural variability of the past 4000 years sometime before the year 2100.

Unfortunately, it does little to dampen the effect of the preceding paragraph. Namely even with the additional CO2 presently in the atmosphere and its accepted small warming effect, Greenland was still warmer in the past.

Abstract is here.

(h/t Climate Depot and C3 Headlines)

2010 could be "hottest year on record"

Throw some more snags on the barbie, mate

So screams the headline in The Times, conveniently forgetting to mention that “on record” means since about 1880, but “hottest year since 1880” doesn’t sound anywhere near as scary. But anyway, it’s a great opportunity to wheel out über-alarmist James Hansen:

CLIMATE scientists have warned that 2010 could turn out to be the warmest year in recorded history [since 1880].

They have collated global surface temperature measurements showing that the world has experienced near-record highs between January and April.

Researchers working independently at the Met Office and Nasa are soon to publish data that reveal the trend is likely to continue for the rest of the year. [Hmm, that’s odd, given that El Niño is fading fast, we’re heading towards La Niña conditions, and sea surface temperatures are heading south rapidly, but if the models say that then it must be true, surely?]

James Hansen [round of applause please], director of Nasa’s Goddard Institute for Space Studies (Giss), a world centre for climate monitoring, said: “Global temperatures, averaged over the past 12 months, were the warmest for 130 years. [Big freaking deal]

“December to February was also the second-warmest of any such period [since 1880].”

Vicky Pope, head of climate change advice at the Met Office, said: “It was a cold winter in Europe but, globally, January to March was one of the seven warmest starts to the year on record [since 1880].

“This year has more than a 50% chance of being the warmest on record [since 1880].

None of this proves anything about a link to man-made emissions. The planet is recovering from the Little Ice Age, so is it any wonder that this decade is warmer than last? And there’s been a strong El Niño, so is it any wonder that the start of this year is warmer than the end of last? Not really. At least there’s a bit of sanity at the end:

John Christy, professor of atmospheric science at the University of Alabama in Huntsville, was cautious about predicting record temperatures for 2010, pointing out that the global datasets for temperature had flaws that could lead to rises being overstated [that’s a polite way of saying “they’re fudged” – Ed]. He said: “Be wary of climate forecasts — Mother Nature always seems to have a trick up her sleeve.”

Yeah, remember her, James Hansen? Mother Nature?

Read it here.

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