Summary of our new research paper published in Scientific Reports
Atlantic tropical cyclones are a persistent threat to Countries surrounding the tropical Atlantic Ocean and Caribbean Sea. The recent devastation on the Island of Dominica is a case in point where Tropical Storm Erica caused flooding and landslides and killed at least 20 people and left more than 50 missing. While these storms are often perceived as a threat to the economies of the Small Island Developing States of the Caribbean Region (primarily because of their potential devastating impacts on life, agricultural productivity and food security), hurricanes also contribute significantly to the water budget across the region by replenishing water reserves and buffering national economies from the threat of drought.
Despite recent advances in our understanding of how climatic change may control tropical cyclone activity on a global scale, there is still no consensus on the extent to which activity in the Atlantic basin is influenced by human activity. Indeed, the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC; Christensen et al. 2013) concluded that there is low confidence in region-specific projections of tropical cyclone activity and that it remains uncertain whether recent changes in Atlantic tropical cyclone activity lie outside the range of natural variability. In order to determine the long-term variability of hurricane activity over the last 1000 years, we have developed an index of long-term hurricane activity known as the Extended Hurricane Activity (EHA) index.
We present the new reconstruction of hurricane activity in a recent paper published by the Nature Publishing Group in the Open Access journal Scientific Reports and show that a strong correlation exists between the EHA index (developed from the published Jamaican lake level record), the Accumulated Cyclone Energy index (ACE) and sea surface temperature variability within the Main Development Region (MDR) of tropical cyclone activity for the modern historical period (Fig. 1).
When extended further back in time (Figure 4 (original article)) hurricane activity appears muted during the Medieval Climate Anomaly (~900–1350 CE) and becomes more variable (and extreme) during the so-called Little Ice Age (~1450–1850 CE), a period of cooler temperatures recorded in the Northern Hemisphere and thought to be associated with a combination of lower solar and enhanced volcanic activity. The index supports evidence for a gradual increase in Atlantic hurricane activity during the industrial period (ca. 1870-present), however, we show that contemporary activity has not exceeded its longer-term natural variability exhibited over last 1000 years.
Lecture by Professor John Smol:“The past matters: Using lake sediments to study the environmental effects of multiple stressors”
There was an excellent turnout from students of the Department of Geography and Geology who found the lecture very insightful. The lecture was followed by numerous questions from the students which led to interesting discussions on the various paleolimnological techniques that Professor Smol uses and the case studies he presented from his work in the Arctic and Canada. We thank Professor Smol for giving a superb lecture!
Manatee Bay, Jamaica
As part of their visit we took John and Chris to Manatee Bay, St. Catherine heading out from Old Harbour Fishing Beach with Mr Charles Moodie. We have been working at Manatee Bay for some years on an extensive sediment core record (15 cores) to reconstruct environmental conditions over the last millennium and investigating marine washover events. To do this we are using various proxy data including ostracods, benthic foraminifera, and micro-XRF sediment geochemistry.
Extending the multiproxy toolkit in Jamaica
As part of our research programme we are working on a number sediment cores from lakes and coastal lagoons around Jamaica. We will be working with the PEARL lab to increase the number of proxies that we use in order to improve our understanding of environmental and climatic change over the last millennium.
St. George’s Lake, Jamaica
Mike joined Chris Grooms and Stefan Stewart (Founder and Head of the Jamaica Cave Association) on a field day around various lakes and ponds across Jamaica to carry out sampling of surface sediments and lake water. The PEARL lab have designed a special coring technique for recovering unconsolidated sediments at the surface-water interface. John and Chris will be looking for the presence of diatoms amongst other paleolimnological indicators, and we are going to have a look at the pollen, ostracods and any other critters we may come across!
We are looking forward to working with John, Chris and colleagues on new and existing palaeoenvironmental projects in Jamaica!
“The past matters: Using lake sediments to study the environmental effects of multiple stressors”
Location: Department of Geography and Geology, Lab 2
Date: Thursday 19th February 2015, 1pm
The lecture will provide fascinating insights into many of the hidden environmental secrets locked within lake sediment records. This will include discussion on (1) how seabirds may act as biovectors to transport nutrients and contaminants from marine environments back to terrestrial ecosystems, and (2) how paleolimnological approaches can be used to study the frequency and ecological effects of past marine flooding events on coastal ecosystems.
All are very welcome to attend, refreshments provided!