27 Jan Ancient Hurricanes Prepare Modern Civilization
We’re all familiar with the effects that hurricanes have in the moment, and the lasting damage they can do. But there’s more to it than that. In fact, a hurricane’s passage can leave evidence that researchers can study even thousands of years later.
These “permanent records” provide researchers with hurricane data that they can compare with historical data regarding the changes in the ocean’s temperature over time, allowing them to create models that might help us predict how climate change may affect future hurricane seasons.
Scientists like Jeffery Donnelly, at the Woods Hole Oceanographic Institutions, use “sediment cores” in order to track the paths of ancient storms in the South Pacific and Atlantic oceans. A sediment core refers to layers of sand and mud that are extracted from lake beds along the coast by using a tube-like mechanism. They provide a record of weather events that can help to corroborate storm and weather models made by computers, providing us with insight into future storm patterns.
These cores can contain an astonishing amount of information. For example, in Falmouth, Massachusetts, scientists extracted cores from Salt Pond which contained data sufficient to examine hurricane patterns going back two millennia.
These samples proved that Cape Cod experienced periods of more intense hurricane activity, particularly during the 1400s through the 1600s. Not only were these storms more frequent, but the records suggest that they were also stronger than those the region has experienced during the 1900s. During the time period of more intense storms, the northwestern Atlantic ocean was relatively warmer than in other time periods.
It’s true that sediment cores taken from a particular region only assist researchers with studying the storm activity in that local area, but as more scientists join these studies, they can be compared with other cores up and down the same coasts. There are also written historical records, and other naturally occurring data, with which to compare them, allowing scientists to model long-term chronologies of hurricane patterns.
Because high ocean surface temperatures fuel hurricanes, it is not surprising that scientists have noticed similar patterns in other areas. For example, sediment cores collected in Florida demonstrated increased frequency and intensity in storm activity during periods of warmer sea temperatures. The same has proven to be true when studying cores extracted in Puerto Rico.
Most people know that hurricanes are relatively uncommon; that’s why they are such a big deal when they do happen. Sometimes it might be ten years or more between hurricanes in a particular region. Contemporary, comprehensive hurricane tracking across the globe began in the 1970s along with the launching of weather satellites, allowing researchers to expand upon what we know from the written records of the past.
Those written records, before 1970, are fairly limited. It’s true that seafarers and coastal communities kept some records of hurricane activity, but these records can be lost, and are, even in the best of circumstances, woefully spotty. The research being conducted with sediment cores and other paleoclimate reconstruction techniques allow scientists to fill in the blanks.
Models of climate are constructed based on this data, and computers can use these models to extrapolate long-term changes in storm patterns, even over the course of decades or centuries. These results are then checked against findings from paleoclimate studies to determine their likely accuracy. In short, if a model can successfully predict a storm pattern from the past using the data, then its predictions for future storm patterns should be taken seriously.
The studies conducted so far indicate that hurricane activity may increase with global warming but may not do so in a uniform manner across the world. Instead, there will be certain hotspots of increased activity, which these models may be able to predict.
Researchers choose the areas where they collect sediment cores very carefully. They look for bodies of water near the coast, like lakes and ponds, which are protected from the ocean itself by a beach barrier. In typical circumstances, only fine sediment ends up in these areas. However, when there is an intense storm like a hurricane, heavier material can be deposited in these natural basins. These layers of heavier material are a sign of hurricanes.
The further down in the sediment layers they probe, the older the layers are. This allows them to determine the time frame for each weather event. Scientists are currently focusing on coastal regions like Vanuatu, the Caribbean, and the coast of the United States. They want to determine whether or not rising ocean temperatures will result in increased hurricane activity in these areas in order to prepare coastal inhabitants for the changes associated with climate change.