The Earth's surface really is getting warmer, a new analysis by a US scientific group set up in the wake of the "Climategate" affair has concluded.
The Berkeley Earth Project has used new methods and some new data, but finds the same warming trend seen by groups such as the UK Met Office and Nasa.
The project received funds from sources that back organisations lobbying against action on climate change.
The project was established by University of California physics professor Richard Muller, who was concerned by claims that established teams of climate researchers had not been entirely open with their data.
He gathered a team of 10 scientists, mostly physicists, including such luminaries as Saul Perlmutter, winner of this year's Nobel Physics Prize for research showing the Universe's expansion is accelerating.
Funding came from a number of sources, including charitable foundations maintained by the Koch brothers, the billionaire US industrialists, who have also donated large sums to organisations lobbying against acceptance of man-made global warming.
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Our biggest surprise was that the new results agreed so closely with the warming values published previously”
Berkeley group founder
"I was deeply concerned that the group [at UEA] had concealed discordant data," Prof Muller told BBC News.
"Science is best done when the problems with the analysis are candidly shared."
The group's work also examined claims from "sceptical" bloggers that temperature data from weather stations did not show a true global warming trend.
The claim was that many stations have registered warming because they are located in or near cities, and those cities have been growing - the urban heat island effect.
The Berkeley group found about 40,000 weather stations around the world whose output has been recorded and stored in digital form.
It developed a new way of analysing the data to plot the global temperature trend over land since 1800.
What came out was a graph remarkably similar to those produced by the world's three most important and established groups, whose work had been decried as unreliable and shoddy in climate sceptic circles.
"Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the US and the UK," said Prof Muller.
"This confirms that these studies were done carefully and that potential biases identified by climate change sceptics did not seriously affect their conclusions."
Since the 1950s, the average temperature over land has increased by 1C, the group found.
They also report that although the urban heat island effect is real - which is well-established - it is not behind the warming registered by the majority of weather stations around the world.
They also showed that in the US, weather stations rated as "high quality" by Noaa showed the same warming trend as those rated as "low quality".
The Berkeley team has chosen to release the findings initially on its own website.
They are asking for comments and feedback before preparing the manuscripts for formal scientific publication.
In part, this counters the accusation made during "Climategate" that climate scientists formed a tight clique who peer-reviewed each other's papers and made sure their own global warming narrative was the only one making it into print.
But for Richard Muller, this free circulation also marks a return to how science should be done.
"That is the way I practised science for decades; it was the way everyone practised it until some magazines - particularly Science and Nature - forbade it," he said.
"That was not a good change, and still many fields such as string theory practice the traditional method wholeheartedly."
This open "wiki" method of review is regularly employed in physics, the home field for seven of the 10 Berkeley team.