WMO: 2017 expected to be third hottest year on record

The World Meteorological Organization (WMO) released its provisional Statement on the State of the Climate this week, estimating that 2017 is likely to be one of the warmest years for global average surface temperature, with many high-impact events including catastrophic hurricanes, floods, heatwaves and droughts.  The Statement was released on the opening day of the United Nations climate change conference in Bonn.

Nacreous clouds

Clouds that have a vivid iridescent appearance. They are formed of small droplets which scatter light in such a way that creates the distinctive luminescent appearance. Nacreous clouds form below -78 °C temperatures at altitudes 68,500 - 100,000 ft above the Earth's surface (in the lower stratosphere) over polar regions.They are also known as Polar Stratospheric Clouds (PSC) or 'mother-of-pearl clouds'.