JoNova

A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


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Did GISS discover 30% more land in the Northern Hemisphere?

… UPDATED with GLOBAL values! The questions get bigger.  (See below) July 18th.

Frank Lansner has been a busy man, and he’s asking some very thought provoking questions.

The Northern Hemisphere has a ratio of 40% land to 60% oceans, and the Hadley Met Centre seems to use a similar ratio (NH HadCrut Series: 58% ocean, 42% land). But  Frank Lansner wondered why, when he graphed the GISS land-data-set alongside the combined-sea-surface-temperatures (CSST), GISS comes up with an “averaged” line that runs much closer to the land data set and not the sea surface set. If it were weighted 60:40 (ocean:land) the combined Northern Hemisphere line ought to run slightly closer to the ocean based temperatures.

So Lansner mixed the land and sea temperatures in different ratios and graphed them and an odd thing occurred. Perhaps there is some good reason for it, but the GISS NH average line is currently running close to a mix that could be almost 70% land, and only 30% ocean. Back in 1985 the NH Average was closer to the sea temps as would be expected. In fact as late as 1995, the NH line still ran at around 40% land area. But somewhere [...]

The mystery deepens — where did that decline go?

Frank Lansner has done some excellent follow-up on the missing “decline” in temperatures from 1940 to 1975, and things get even more interesting. Recall that the original “hide the decline” statement comes from the ClimateGate emails and refers to “hiding” the tree ring data that shows a decline in temperatures after 1960. It’s known as the “divergence problem” because tree rings diverge from the measured temperatures. But Frank shows that the peer reviewed data supports the original graphs and that measured temperature did decline from 1960 onwards, sharply. But in the GISS version of that time-period, temperatures from the cold 1970′s period were repeatedly “adjusted” years after the event, and progressively got warmer.

The most mysterious period is from 1958 to 1978, when a steep 0.3C decline that was initially recorded in the Northern Hemisphere. Years later that was reduced so far it became a mild warming, against the detailed corroborating evidence from raobcore data.

Raobcore measurements are balloon measures. They started in 1958, twenty years before satellites. But when satellites began, the two different methods tie together very neatly–telling us that both of them are accurate, reliable tools.

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Hide the decline and rewrite history?

Human emissions of carbon dioxide began a sharp rise from 1945. But, temperatures, it seems, may have plummeted over half the globe during the next few decades. Just how large or how insignificant was that decline?

Frank Lansner has found an historical graph of northern hemisphere temperatures from the mid 70′s, and it shows a serious decline in temperatures from 1940 to 1975. It’s a decline so large that it wipes out the gains made in the first half of the century, and brings temperatures right back to what they were circa 1910. The graph was not peer reviewed, but presumably it was based on the best information available at the time. In any case, if all the global records are not available to check, it’s impossible to know how accurate or not this graph is. The decline apparently recorded was a whopping 0.5°C.

But, three decades later, by the time Brohan and the CRU graphed temperatures in 2006 from the same old time period, the data had been adjusted (surprise), so that what was a fall of 0.5°C had become just a drop of 0.15°C. Seventy percent of the cooling was gone.

Maybe they had good reasons for making [...]

Scandinavia-gate

Yet again,  we have a situation where the data doesn’t match the full-gloss coloured graphs produced by the PR agency for global warming called the IPCC.

Frank Lansner and Nicolai Skjoldby have started a new blog Hide The Decline, and posted that Scandinavian data shows clearly that temperatures got markedly cooler from 1950-1970, before they began rising again, and even after the warming, they only appear to be back where they were. But, all the IPCC graphs minimize the cooling. It would be reasonable to conclude from the data that the temperature today in Scandinavia is roughly similar to that of the 1930′s. But, you’d never know this from looking at the IPCC graphs.

Scandinavian Temperatures: 25 data series combined from The Nordklim database (left), compared to the IPCC's temperature graph for the area.

The IPCC needs to come forward and explain why its graphs are so different.

There is no “hockey stick warming” here. There is no unprecedented heat, and there is no good correlation with the rise of carbon dioxide either. Sure, this is just one region, not the globe, but this is yet another example of how the IPCC has not presented an honest assessment of the information.

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