The United Nations weather agency says the past 10 yearswere likely the hottest decade since scientists began keeping records.In a new report, the World Meteorological Organization, or WMO,blames the rising temperatures mainly on greenhouse gases produced by human activities."Average temperatures for the five-year, 2015-to-2019 and 10-year, 2010-to-2019 periodsare almost certain to be the highest on record," the WMO said.The report predicted that 2019 would become the second- or third-warmest year on record.Final temperature measurements will not be available for several months.Petteri Taalas is the Secretary-General of the WMO.He says severe heatwaves and floods that used to happenabout once every hundred years have become "regular" events."Countries ranging from the Bahamas to Japan to Mozambiquesuffered the effect of devastating tropical cyclones.Wildfires swept through the Arctic and Australia," he noted.Taalas said that one of the main effects of climate change is the lack of predictable rainfall.This presents a threat to successful harvests and will likely createfood security problems in some countries in the future, he said.The report said climate change was a main driver of a recent increasein world hunger after 10 years of decrease.It estimated that about 820 million people suffered from hunger in 2018.The WMO said that weather disasters have displaced millions of people this yearand affected rainfall from India to northern Russia, to the central United States and other areas.Oceans, which take in an estimated 90 percent of the extra heatproduced by greenhouse gases, are now at their highest recorded temperatures.Sea water is also 25 percent more acidic than it was 150 years ago, the report said.This is threatening ocean environments that provide food and jobs for billions of people.Levels of carbon dioxide in the atmosphere reached a record407.8 parts per million in 2018 and continued to rise in 2019.Experts say carbon dioxide can be damaging because it can remain in the atmospherefor hundreds of years and in the ocean for even longer.On Monday, at the opening of a climate meeting in Spain,United Nations Secretary-General Antonio Guterreswarned that 400 parts per million had once been considered "unthinkable."The UN Climate Change Conference brings together representatives from around the worldto seek solutions to reduce greenhouse gas emissions.Last year, the UN's Intergovernmental Panel on Climate Changeset a goal for countries to limit temperature increases to 1.5 Celsius or below.The group said this target could be reached by reducing greenhouse gasesand restructuring the world economy to expand renewable energy sources.The UN reported last week that the world needed to cut carbon emissionsby 7.6 percent each year, every year, until 2030, to reach the 1.5 Celsius temperature goal.The WMO's Petteri Taalas urged the world to quickly launch stepsaimed at reducing temperatures before it is too late."If we do not take urgent climate action now, then we are headingfor a temperature increase of more than 3°Celsius by the end of the century,with ever more harmful impacts on human wellbeing," he said.