Row over climate ‘hockey stick’

A row has erupted over one of the most provocative symbols of global warming – the iconic “hockey stick” graph.

This record of Northern Hemisphere temperature variation in the last 1,000 years shows a recent warming trend apparently linked to human activities.
New work in the journal Geophysical Research Letters questions its validity, challenging the way it was originally put together.

Other scientists say the work simply highlights a technical issue.