Member Article

Northern Hemisphere Is Hotter Than Ever

The temperature of the northern hemisphere has increased more in the last century than at any time in the past millennium, claims a report published in Science this week.

The study finds that the number of ‘hot spots’ has increased dramatically in the Northern Hemisphere in over the last 100 years compared to the past 1200 years – adding to the growing evidence of wide-scale global warming. The team at the Climatic Research Unit team, University of East Anglia, analysed temperatures from 1856 onwards to establish the spatial extent of recent warming, and compared it with evidence from as far back as AD 800 using tree rings, ice cores and shells. The study found evidence for periods of significant warmth during medieval times and for clearly colder periods (1580 – 1850) during the so-called “Little Ice Age”. However their key conclusion was that the 20th century stands out as having unusually widespread warmth, compared to all of the natural warming and cooling episodes during the past 1,200 years. The research team gathered climate change data from a number of regions in the Northern Hemisphere including investigating the rings of long-life evergreen trees, which had been cored to reveal the patterns of wide and narrow tree rings over time – wider rings relating to warmer temperatures. Ice was also drilled from cores of Greenland ice sheets to reveal chemical composition of the ice when the atmosphere was warmer.

They also used a record developed from diaries of people living in the Netherlands and Belgium over the past 750 years that revealed for example the years when the canals froze.

This was posted in Bdaily's Members' News section by Ruth Mitchell .