future scenarios Posts

New Study Explores Consequences of Projected Climate Changes in Temperature and Rainfall for Puerto Rico


New Study Explores Consequences of Projected Climate Changes in Temperature and Rainfall for Puerto Rico

Consequences could include increasing energy demands for cooling, increasing likelihood of drought and shifts in ecological life zones

Photo Credits: (Top) Cerrillos Dam, Cordillera Central mountain range (USACE, 2013) and (Bottom) NOAA National Weather Service, EFE/Archive, Carraizo Reservoir

Photo Credits: (Top) Cerrillos Dam, Cordillera Central mountain range (USACE, 2013) and
(Bottom) NOAA National Weather Service, EFE/Archive, Carraizo Reservoir

SAN JUAN, PR — A new study published in the Journal of Applied Meteorology and Climatology explores the implications of various climate change projections for Puerto Rico and presents maps of potential future temperature and rainfall scenarios that indicate substantial changes in temperature and rainfall island-wide to differing degrees depending on decade and location. The results show temperatures increasing from 4.6 °C to 9 °C (8 °F to 16 °F), and rainfall decreasing  up to 50% by the end of the century. The study details how these changes interact with the topography of the island and shows trends of increasing cooling degree days, increasing annual number of days without rain, and shifting ecological life zones as temperature and rainfall patterns change over the next century. The implications vary depending on which climate models and greenhouse gas emission scenarios are used, but all show significant increases in temperatures and decreasing rainfall by the end of the century.

Researchers from the International Institute of Tropical Forestry (IITF), U.S. Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit (NCCFWRU) and the University of Puerto Rico (UPR) began work in 2012 with support from the U.S. Geological Survey, the U.S. Fish and Wildlife Service, and the U.S. Forest Service. Efforts in Puerto Rico to prepare infrastructure and natural resource managers for climate change had been hindered for years by the lack of available future climate information specific to the island. Results from this study begin to fill an information gap that had been recognized by local researchers since at least 2002, in UPR round table discussions, at Puerto Rico Climate Change Council meetings and in their preeminent report “Puerto Rico’s State of the Climate 2010-2013” and conferences like Climate Change in the Caribbean at Inter American University Law School in 2011 and 2015.

“Through this work we are beginning to develop a better understanding of where in Puerto Rico changes in temperatures and rainfall will occur,” stated lead scientist Dr. Azad Henareh, now with Colorado State University, “This research helps us understand that these changes could be substantial.  More needs to be done to shed light on the particular characteristics of these expected changes across the complex topography of the island.”

Dr. Henareh and the team were able to model and map future climate changes for the first time specific to Puerto Rico’s unique topography and ecosystems. This study is the third of a suite of linked research projects by NCCFWRU and IITF with support from the Caribbean Landscape Conservation Cooperative (CLCC) and builds on the studies previously done. The first study completed for the Department of the Interior’s Southeast Climate Science Center and the CLCC was conducted by Dr. Katharine Hayhoe of Texas Tech University. She produced Puerto Rico-specific climate projections from twelve statistically downscaled Global Climate Models (GCMs). These data were used by a team led by Dr. Ashley E. Van Beusekom of IITF to model the effects of changing land cover on streamflow in Puerto Rico, including Vieques and Culebra. This third study, Henareh et al. 2016, provides results for future changes in temperature, rainfall, evapotranspiration, annual cooling degree-days and ecological life zones.

Projected life zones from the average of all models under the three emission scenarios (the emission scenarios do not apply to the first time interval)

Projected life zones from the average of all models under the three emission scenarios (the emission scenarios do not apply to the first time interval).

The study suggests we will see shifts in ecological life zones from wetter to drier environments with the possibility of losing most, if not all, of the wettest life zones at upper elevations. Future climatic conditions may also result in new, drier ecosystems in southwestern Puerto Rico. Consequences of projected changes in temperature and rainfall are not just limited to plants and animals but to Puerto Rico’s infrastructure and economics as well. The team modeled annual cooling degree-days as a proxy index for air-conditioning energy demand and found significant increases in the number of days annually at which one might need to use energy for cooling buildings.  Another consequence of the potential changes the island could face is more extreme water deficits, as Dr. Van Beusekom’s work shows, a daunting possibility as Puerto Rico had one of the worst droughts in its history in 2015 with 5-day water rationing in many metropolitan communities.

“By making explicit the range of potential climate outcomes faced by the island, this study will help focus a number of important conversations on drought, water supply, and energy.” Gerard McMahon, Director of the U.S. Geological Survey Southeast Climate Science Center, added that “continuing work funded by the DOI SE Climate Science Center should provide additional detail about expected climate conditions and support decisions under consideration by the public, the government, and the private sector.”

Dr. William Gould, Research Ecologist for the International Institute of Tropical Forestry and one of the study authors, stated that “The Caribbean Landscape Conservation Cooperative has a strong interest in science delivery to address climate change issues. Now that this study has been completed, the Cooperative will be working to make sure the information is widely available and useful to managers and researchers.” Dr. Gould presented findings of the study at today’s VII Puerto Rico Climate Change Council Summit at the Condado Plaza Hotel.



Available for Use by Media Professionals:

The full published scientific article.

High-resolution graphics in English and Spanish for temperature and rainfall by scenario (dropbox folder 1)

Animation (.mp4 files/dropbox folder 2; YouTube)

Descargar las proyecciones de la temperatura, la precipitación, la evapotranspiración y las zonas de vidas ecológicas en el mapa interactivo del CLCC.

Link to visualize and download the climate data on the Interactive Map of the CLCC Data Center (click on “Future Scenarios” and then click on the search bar to browse all the available data layers. Select the layers you would like to view and then close the search box to view the data on the map).





Note: The results represent three scenarios: best, medium and worst case outcomes for Puerto Rico at three timer periods. These scenarios provide a boundary for what we might expect to occur and serve as storylines describing future characteristics for demographic changes, economic growth, and technological change (labeled B1, A1B and A2). What Puerto Rico experiences in 2030, 2060, or 2090 will depend on these characteristics and the level of carbon pollution emitted by the world-wide community in the coming decades. They are standard climate scenarios frequently used by researchers with the Nobel peace prize winning Intergovernmental Panel on Climate Change. Colloquially you can say that the B1 scenario is the “best case scenario”, A2 is the “worst case scenario”, and A1B is “middle of the road”.