Rains have brought relief from the heat in parts of the country over the past few weeks, but the heat across much of Colombia has been far more than just uncomfortable this year. It’s been dangerous.

And it could get worse.

An October report from the U.K. risk consulting firm Verisk Maplecroft lists Cartagena and Barranquilla in the top 25 among more than 1,300 major world cities most at risk of lost productivity from climate change-related heat stress.

Even a leisurely stroll through the streets of Cartagena at midday can be a sweltering slog. Anything more strenuous can be risky without taking appropriate precautions.

Too hot to work

But as the planet gets hotter, there will be more and more days per year during which the heat is too risky for most outdoor labor.

Workers in the manufacturing, agriculture and construction industries are at the greatest risk according to Richard Hewston, a researcher with Verisk Maplecroft.

Symptoms of heat stress include dizziness, fatigue, nausea and — in extreme cases — death.

“Governments and businesses need to identify which assets and which sectors are most at risk from heat stress and what mitigation measures they can put in place,” said Hewston.

But a warmer climate can have far more severe impacts than loss of productivity.

Colombia already feeling the heat

Several parts of Colombia have been suffering extreme heat and drought, particularly along the northern Caribbean coast. Over the past three years, dozens of children in the La Guajira department have died of thirst and malnutrition.

A June heat wave sent temperatures in Cartagena soaring as high as 40 degrees Celsius (104 degrees Fahrenheit). At least one elderly woman died as a result, according to an El Tiempo report.

The report also predicts that roughly half of the world’s population will live in areas with an “extreme risk” of heat stress by the year 2045. Most of the highest risk cities are in southeast Asia.

Warm days might feel nice in Colombia’s normally chilly capital city of Bogotá, but warmer than average months and years can be disastrous.

Setting new records

October 2015 was the hottest October ever recorded — by a whopping 1.76 degrees Fahrenheit or roughly 1 degree Celsius — according to the U.S. National Ocean and Atmospheric Administration (NOAA).

And it was only the latest in a string of record-breaking months this year, which will almost certainly become the warmest on record.

Eight out of the first ten months in 2015 set new records for average global temperatures, virtually guaranteeing that the year overall will be a record-breaker.

If so, it would beat out 2014, which currently holds the title of warmest year since NOAA started keeping track of global temperatures in 1880.

El Niño, a global climate phenomenon characterized by a warmer than average Pacific Ocean, may be responsible for much of the unusually warm weather. This year’s El Niño may be the strongest on record.

In Colombia, El Niño tends to cause high temperatures and severe drought. But it unpredictable and can also cause unusually strong rains.

The most recent previous severe El Niño cycle, which occurred in 1997, caused hundreds of millions of dollars worth of damage in Colombia.