With the climate change debate as heated as ever, how do scientists reconstruct what the weather was like in the past? Jon Evans looks at the detective chemistry behind such environmental forensic work © Pete Bucktrout/British Antarctic SurveyThe Earth is not particularly good at keeping records, especially of its past climate. Like those of a disorganised businessman, its climate records are difficult to find, hard to interpret and often contradictory. But like diligent auditors, scientists are making great efforts to get to the bottom of the Earth’s disorganised records, both to understand how the Earth’s climate behaved in the past...