Climate change (Class of 2019)
Global warming was "discovered" while the world was not warming.
"Discovery of global warming" ... not a single event, but a century-long process
(as Weart describes).
In this context, "global warming" does not simply mean rising of global mean temperature.
"Global warming" or "anthropogenic climate change" (in this context):
a kind of climate change (which has multiple aspects including rising global mean temperature)
caused by enhanced greenhouse effect,
which is mainly caused by increase of carbon dioxide content in the atmosphere,
which is mainly caused by human activity of burning fossil fuels.
- Black dots in the graph: global mean surface temperature, as compiled by Japan Meteorological Agency
- How the numerical values were obtained? ... another story.
- If "discovery of global warming" means "detection of rise of global mean temperature",
it occured around 1990. It is actually two things combined:
- Recognition of rapid rise of temperature since late 1970s to 1990s
- Recognition of one century trend of temperature since 1890s (with newly available retrospective analysis)
- I think this more important: theory-based outlook of future global warming due to enhanced greenhouse effect in the late 1970s.
(Note that the record of global mean tempearture available at the time showed cooling (temperature decreasing) trend since 1940s.)
Approaches in earth science: mathematical-physical vs. natural history
- mathematical physics: thinking from cause to effect with principles of physics
- natural history: thinking from "effects" to causes
- (This characterization is too much simplified.)
- (This contrast is somewhat similar to "deduction vs. induction", but not the same.)
Discovery of global warming as future outlook : achieved by mathematical-physical approach
- Numerical models based on physical principles had been constructed.
- Carbon dioxide content in the atmosphere was observed regularly since 1958,
and its increase (main cause of g.w.) was evident around 1963.
- Anticipated "effect": rise of global mean temperature and associated various changes.