Peter Langdon Ward by the Montreal Protocol on Substances that Deplete the Ozone Layer led to the Global Warming Hiatus from 1998 to 2013, during which no statistically significant warming occurred. Warming began again in August 2014 when Bárðarbunga volcano in Central Iceland erupted 85 square kilometers of basaltic lava in six months—the largest effusive volcanic eruption since 1783. As with most effusive volcanic eruptions, this one did not form cooling aerosols in the stratosphere. All of this research is explained in detail at WhyClimateChanges.com, is summarized in a book aimed primarily at non-scientists, What Really Causes Global Warming? Greenhouse Gases or Ozone
Montreal Protocol Antarctic Survey scientists Joe Farman, Brian Gardiner and Jonathan Shanklin published results of abnormally low ozone concentrations above Halley Bay near the South Pole. They speculated that this was connected to increased levels of CFCs in the atmosphere. It took several other attempts to establish the Antarctic losses as real and significant, especially after NASA had retrieved matching data from its satellite recordings. The impact of these studies, the metaphor 'ozone hole', and the colourful visual representation in a time lapse animation proved shocking enough for negotiators in Montreal, Canada to take the issue seriously. Also in 1985, 20 nations,