Why some tree ring records haven’t tracked recent warming

Science Focus

original post »

Cores of wood drilled from trees so the annual growth rings can be studied.

Scott St. George

The release of e-mails hacked from University of East Anglia climate scientists in 2009 (unimaginatively dubbed “Climategate” in media scandalese) generated about as much public discussion as any report of the science has. Long after the initial attention died down and a number of independent investigations found no evidence of scientific malpractice, snippets of quotes from the e-mails continue to pop up in conversations and opinion columns.

The most famous snippet related to reconstructions of past climate based on tree rings. One researcher, describing work putting together a graph, mentioned using “Mike’s Nature trick” to “hide the decline." It was exactly the nefarious-sounding sort of language that those who combed the e-mails for dirt wanted to find. Of course, it turned out to simply be a casual description of something much more mundane. “Mike’s Nature trick” was to display the instrumental temperature record and tree ring data on a graph—as climate scientist Michael Mann had done for a paper published in Nature.

So what about “the decline”? It’s no secret that many tree ring climate records from the Arctic diverge from instrumental data around the 1950s, failing to show the warming we’ve observed. So for some reconstructions, data from the second half of the 20th century is known to be inaccurate. In many ways, the divergence itself is much more interesting than arguments about unremarkable e-mails. Tree ring researchers have puzzled over what could explain the odd behavior of these Arctic trees.

Read 8 remaining paragraphs | Comments

 
#science 
 » see original post http://feeds.arstechnica.com/~r/arstechnica/science/~3/r0c5m2sjP7E/
See Zazzle gifts tagged with 'science'