Commentary Richard Ernst
Earth's History and Modern Climate Change
This is an exciting conference series with its focus on Life / Earth Sciences / Sustainable Global / Regional Development.
As a geoscientist I specialize in huge volcanic events known as Large Igneous Provinces
which occur every 20-30 million years and which can cause catastrophic change climate including mass extinctions.
These volcanic events along with other drivers such as meteorite impact, plate tectonics, biological evolution, and other process,
contribute to events of global warming (Hothouse), global cooling (Icehouse, i.e. Snowball Earth or regional glaciations), anoxia,
stepwise oxygenation, acid rain/ ocean acidification, enhanced hydrothermal and terrestrial nutrient fluxes, and mercury poisoning.
I think that discussions of modern climate change can directly benefit from our rapidly increasing knowledge through geoscience of Earth’s history of climate change over billions of years.
I am convinced that Earth’s history of climate change (regardless of cause) can provide a robust context for modern climate change without diminishing the impact of anthropogenic drivers in the latter.
For instance, characterization of ancient global warming events can provide new strategies for reduction of elevated CO2, and provide warning of unanticipated consequences of modern global warming. One example of the former is that weathering of mafic and ultramafic rocks, acts as powerful sinks for atmospheric CO2, and thus suggests a role for these rock types in carbon sequestration efforts.
A simple cautionary tale is that the Earth has experienced many periods of dramatic climate change, some of which resulted in mass extinction events where a majority of life on Earth was wiped out. An important message from geological history is that Earth’s climate is continually changing, sometimes dramatically and with catastrophic effects on life, and therefore, the risk to humanity of modern climate change is real.