The speed and extent of current global warming exceeds any similar event in the past 2,000 years, researchers say.
They show that famous historic events like the "Little Ice Age" don't compare with the scale of warming seen over the last century.
The research suggests that the current warming rate is higher than any observed previously.
The scientists say it shows many of the arguments used by climate sceptics are no longer valid...
...Today's warming, by contrast, impacts the vast majority of the world.
"We find that the warmest period of the past two millennia occurred during the 20th Century for more than 98% of the globe," one of the papers states.
"This provides strong evidence that anthropogenic (human induced) global warming is not only unparalleled in terms of absolute temperatures but also unprecedented in spatial consistency within the context of the past 2,000 years."...
..."They have done this across the globe with more than 700 records over the past 2,000 years; they have corals and lakes and also instrumental data," said Prof Daniela Schmidt from the University of Bristol, UK, who was not involved with the studies.
"And they have been very careful in assessing the data and the inherent bias that any data has, so the quality of this data and the coverage of this data is the real major advance here; it is amazing."
Many experts say that this new work debunks many of the claims made by climate sceptics in recent decades.
"This paper should finally stop climate change deniers claiming that the recent observed coherent global warming is part of a natural climate cycle," said Prof Mark Maslin, from University College London, UK, who wasn't part of the studies.
"This paper shows the truly stark difference between regional and localised changes in climate of the past and the truly global effect of anthropogenic greenhouse emissions."...