Climate change is driving much drier conditions in Africa's Sahel belt, which has experienced a 50-percent hike in record dry months in recent decades, scientists said.
Shifting climate patterns, meanwhile, have made parts of the United States, northern Europe and north Asia wetter, driving worsening flooding and extreme rainfall, said the Potsdam Institute for Climate Impact Research in Germany.
Over the 1980-2013 period the scientists studied, record wet months rose by 25 percent in the east and central United States, for instance.
Lead author Jascha Lehmann told the Thomson Reuters Foundation the researchers had been "a little bit surprised by the very strong signal" on drying in Africa.
The findings suggest efforts to cut planet-warming emissions faster are crucial, he said, as "there are limits" to how much people can adapt if drought continues to worsen in the Sahel, a semi-arid zone that lies south of the Sahara desert.
While occasional record-setting months are not unusual, the uptick in record dry months was significant, he said.
"By injecting huge amounts of greenhouse gases into the atmosphere, humankind has loaded the dice," he added.
The research, published this week, looked at data from about 50,000 meteorological stations around the world, and found tropical and sub-tropical areas were hitting more records for dry weather.
Countries in higher latitudes in the northern hemisphere, however, saw more wet weather over the same period.
In the Sahel, about one in three dry-month records would not have occurred without long-term climate change, said Dim Coumou of the Dutch Institute for Environmental Studies.
Worsening droughts are making life far more precarious for herders and farmers in the region, African officials said on the sidelines of the U.N. climate negotiations in Poland this week.
Madeleine Diouf Sarr, the head of Senegal's climate change unit, said drought over the last three years there had triggered payouts under the African Risk Capacity (ARC) insurance scheme.
That programme aims to spread the risk of worsening losses from extreme weather by building an insurance pool of African nations including Mali, Burkina Faso, Niger and Senegal.
Payouts go to governments, which can then get quick aid to farmers and herders who have lost crops and animals.
Drought in Senegal will probably be a recurring problem requiring a national strategy to address it, Sarr said.
Other responses - from improved social welfare schemes that channel cash to farmers in bad times, to efforts to diversify incomes or provide access to formal financial services - also can help communities cope with drought, researchers said.
"You cannot stop a drought coming, but you can reduce the impact," said Sylvie Wabbes, a resilience officer with the U.N. Food and Agriculture Organization.
Worsening drought is putting growing strain on the budgets of Sahel nations, and a catastrophic drought across broad areas of sub-Saharan Africa could cost as much as $3 billion in emergency aid to address, according to an analysis by ARC.
Lehmann of the Potsdam Institute said intensifying impacts were one reason efforts to hold global temperature rise to between 1.5 and 2 degrees Celsius above pre-industrial times - the goal of the 2015 Paris Agreement - were urgent.
"It is worrying that we see significant increases of such extremes already at just 1 degree of global warming," he said. "It will be a different world if we don't hold temperature down." (Reporting by Laurie Goering @lauriegoering; editing by Megan Rowling. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, climate change, resilience, women's rights, trafficking and property rights