Amid one of the worst droughts in recent memory, Costa Ricans already are feeling the damage of extreme weather changes that come with climate change, experts said on Wednesday, at the Climate Vulnerability Forum’s regional workshop, held this week in San José.

“Central latitudes are getting drier but experiencing heavy downpours when it does rain,” said Matthew McKinnon, a specialist at the U.N. Development Program, who has been involved with the forum since its start five years ago. “Coastal erosion is causing some islands to disappear entirely.”

These disappearing islands already have been documented in Costa Rican waters, officials at the National System of Conservation Areas (SINAC) warned, and a larger threat looms for habitats in the region that lie beneath the ocean. Earlier this month, The Tico Times reported that experts expect the Mesoamerican Barrier Reef – which runs from Mexico to Honduras – to collapse by the year 2060.

Conference attendees also warned of the more abstract effects of climate change.

“Climate change means 50, 60 or 70 hot days will happen each year,” McKinnon said. “We know from the science of ergonomics that when it is hot people work less effectively. By the end of the century these losses could represent significant proportions of GDP.”

Some research shows that once temperatures climb above 26°C (78°F), productivity falls by 2.4 percent with every celsius degree of increase.

Started in 2009 in the Maldives, CVF brings together the countries that have the most to lose if climate change is not addressed. Most of these countries are located in the tropics and near the equator, and they face threats ranging from massive decreases in food production to territorial loss from rising ocean levels. As a region, Central America faces threats to its biodiversity as rising temperatures kill off climate-sensitive species.