Michel Jarraud

If you spend a lot of time talking to scientists about climate change, there's one word you'll hear time and time again, and yet it's hardly ever mentioned in the public discussion of climate change. The word is "non-linear."

More than 100,000 people have had to evacuate from their homes in the bordering areas of Paraguay, Uruguay, Brazil and Argentina due to severe flooding in the wake of heavy summer rains brought on by El Nio, authorities said on Dec 26. 

The year 2015 is shaping up to be the hottest on record, the UN's weather agency said Nov. 25, days before a UN summit opens in Paris to craft a climate rescue pact.
 
Based on data for the first 10 months of the year, "We feel very confident... that 2015 will be the warmest year on record," said Michel Jarraud, head of the World Meteorological Organization.
 

Concentrations of carbon dioxide and other greenhouse gases in the atmosphere hit a new high in 2014, the UN said on Nov 9, warning the resulting climate change was moving the world into "unchartered territory."

Without reforms, the world will be plunged into a water crisis that could be crippling for hot, dry countries, the United Nations warned March 20.

In an annual report, the U.N. said abuse of water was now so great that on current trends, the world will face a 40-percent "global water deficit" by 2030 -- the gap between demand for water and replenishment of it.

The year 2014 was the hottest on record, "consistent" with a changing climate, the UN's weather agency said Feb. 2.
      
Average global air temperatures in 2014 were 0.57 degrees Celsius (1.03 degree Fahrenheit) higher than the long-term average of 14 C (57.2 F) in a 1961-1990 reference period, the World Meteorological Organization (WMO) said in a statement.
      

With temperature data showing 2014 currently tied for the hottest year on record, the U.N. weather agency on Dec. 4 rejected claims that global warming has paused.

The World Meteorological Organization said the global average temperature in January-October was 0.57 Celsius (1.03 Fahrenheit) above average, the same as in record hot year 2010.

The amount of greenhouse gases in the atmosphere reached a new record high in 2013, propelled by a surge in levels of carbon dioxide, according to the World Meteorological Organization.

Surging levels of carbon dioxide sent greenhouse gases in the atmosphere to a new record in 2013, while oceans, which absorb the emissions, have become more acidic than ever, the UN said on Tuesday.