Geneva, July 10 -- The world could see annual global temperatures break a key threshold for the first time in the coming five years, the UN weather agency said. WMO said forecasts say there's a 20% chance global temperatures will be 1.5 degrees Celsius higher than the pre-industrial average in at least one year between 2020 and 2024. The 1.5 C mark is the level countries agreed to cap global warming at in 2015. While a new annual high might be followed by several years with lower average temperatures, breaking that threshold would be seen as further evidence that international efforts to curb climate change aren't working....