The Earth's surface really is getting warmer, a new analysis by a US scientific group has concluded.
The Berkeley Earth Project has used new methods and some new data, but finds the same warming trend.
The Berkeley group says it has also found evidence that changing sea temperatures in the north Atlantic may be a major reason why the Earth's average temperature varies globally from year to year.
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.
The biggest surprise was that the new results were very close with the warming values published previously.
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.
These studies were done carefully and potential biases identified by climate change sceptics did not seriously affect the 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.
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.
This open "wiki" method of review is regularly employed in physics, the home field for seven of the 10 Berkeley team.
The Berkeley group does depart from the "orthodox" picture of climate science in its depiction of short-term variability in the global temperature.
The El Nino Southern Oscillation (ENSO) is generally thought to be the main reason for inter-annual warming or cooling.
But by the Berkeley team's analysis, the global temperature correlates more closely with the state of the Atlantic Multidecadal Oscillation (AMO) index - a measure of sea surface temperature in the north Atlantic.
There are theories suggesting that the AMO index is in turn driven by fluctuations in the north Atlantic current commonly called the Gulf Stream.
The team suggests it is worth investigating whether the long-term AMO cycles, which are thought to last 65-70 years, may play a part in the temperature rise, fall and rise again seen during the 20th Century.
But they emphasise that anthropogenic global warming (AGW) driven by greenhouse gas emissions is very much in their picture.
The team next plans to look at ocean temperatures, in order to construct a truly global dataset.
The Berkeley Earth Project has used new methods and some new data, but finds the same warming trend.
The Berkeley group says it has also found evidence that changing sea temperatures in the north Atlantic may be a major reason why the Earth's average temperature varies globally from year to year.
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.
The biggest surprise was that the new results were very close with the warming values published previously.
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.
These studies were done carefully and potential biases identified by climate change sceptics did not seriously affect the 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.
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.
This open "wiki" method of review is regularly employed in physics, the home field for seven of the 10 Berkeley team.
The Berkeley group does depart from the "orthodox" picture of climate science in its depiction of short-term variability in the global temperature.
The El Nino Southern Oscillation (ENSO) is generally thought to be the main reason for inter-annual warming or cooling.
But by the Berkeley team's analysis, the global temperature correlates more closely with the state of the Atlantic Multidecadal Oscillation (AMO) index - a measure of sea surface temperature in the north Atlantic.
There are theories suggesting that the AMO index is in turn driven by fluctuations in the north Atlantic current commonly called the Gulf Stream.
The team suggests it is worth investigating whether the long-term AMO cycles, which are thought to last 65-70 years, may play a part in the temperature rise, fall and rise again seen during the 20th Century.
But they emphasise that anthropogenic global warming (AGW) driven by greenhouse gas emissions is very much in their picture.
The team next plans to look at ocean temperatures, in order to construct a truly global dataset.
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