Till now, researchers relied on the coastal lake sediments or coral isotopes to date hurricanes which took place in past, but now shipwrecks are also seen as evidence of hurricane activities. The researchers at Arizona State University examined data from 657 shipwrecks. They compared the data collected with tree ring data to give precise date to hurricanes. The study results have been published in the journal PNAS.

“We found that in the years when many ships wrecked in the Caribbean, the trees in the Florida Keys showed the same signal that trees show during hurricanes. So, that gave an indication that we could use shipwreck records as a proxy for hurricane activity”, said Jason Thomson, author of the new paper.

As tree rings cannot alone give any precise idea about hurricane but if combined with data from shipwreck, an accurate measurement can be arrived at. Earlier methods employed by using lake sediments have limitation that prediction could only be made for hurricanes that occurred within a century. However, with shipwrecks, a new marker of hurricane, the events that occurred within 10 to 15 years can also be estimated with precision.

The data collected from shipwreck and tree ring shows that there was a 75% decline in hurricane activity between 1645 and 1715. The period is known for being cooler because of reduced sunspot activity resulted in cooler sea surface temperatures. And this low level of temperature at sea surface suppressed hurricane activity. The causes of hurricane cannot be realized through such a data.

The idea of using shipwreck for the first came to Valerie Trouet and her coauthors at Hotel Congress during a science conference in 2013. Trouet is a lead author of the study and also an associate professor in the UA Laboratory of Tree-Ring Research. According to Valerie, through this collected data they will be able to extend Caribbean hurricane record back in time, which would improve their understanding of hurricane variability.