The study, published in the Science journal, found that the northern hemisphere experienced its most widespread warmth late in the late 20th century,
The findings support evidence linking greenhouse gas emissions to climate change.
Researchers from the University of East Anglia measured changes in tree rings, fossil shells and ice cores from 14 sites in the northern hemisphere to assess temperature fluctuation since the year 800.
They also examined people's diaries from the last 750 years to gain information about weather, as well as analysing instrument measurements of temperatures from 1856 onwards, to work out the geographical extent of recent warming.
They said climate change in the last 100 years is more striking that either the so-called Medieval Warm Period (AD870 - 1170) or the much colder periods of the Little Ice Age (1580 - 1850).
The findings of Timothy Osborn and Keith Briffa reinforce other evidence of global warming, that the 20th century stands out as having unusually warm temperatures.
The present warm period that began in the late 20th century is the most widespread and longest temperature anomaly of any kind since the ninth century, the study said.
The research included looking at ring patterns in evergreen trees growing in Scandinavia, Siberia and North America, with wider rings indicating warmer temperatures.
The chemical composition of ice from cores drilled from Greenland ice sheets showed which years were warmer than others.
The research comes a day after a separate study by Australian journalists found global warming is already causing health risks across the globe due to rising sea levels, hotter weather and other climatic changes.