Science Journey: Snowballs in the Desert: Studying Climate Transitions in Earth's Deep Past

I'ts hard to give an exact number of years, but research from modern climate scientists suggests that we need to make fundamental changes to our energy system by 2030 to avoid the worst effects of climate change.

Generally, we need to cut back on the burning of fossil fuels and switch our energy production to renewables like solar and wind power. But there are also ways to draw out and sequester carbon from the atmosphere, the most low-cost and low-tech way being to just plant lots of trees! The reforestation (with proper maintenance) pulls carbon from the atmosphere and stores it as biomass in the form of trees. Though relatively short-term storage by geologic standards, it could make a big difference for combatting current climate change.

It does via volcanic eruptions and the silicate weathering cycle I mention in the talk. Also, many of the fossil fuels that we are burning are themselves buried in rocks.

Increasing the greenhouse gas concentrations will generally cause warming of the climate.

They are similar ideas. The "Ice Ages" that we usually think about (with saber tooth tigers and mammoths) involve a series of large scale glaciations that have fluctuated over the last ~400,000 years. They involved a lot of ice over much of the high latitude continents, however the ice sheets never made it down to the equatorials. Snowball Earth is a similar but much more extreme event were ice sheets entirely covered the continents and sea ice covered most if not all the oceans.

Climate change might affect plate tectonics in some minor ways, but not substantially .

Rocks are cool and all around us! Plus, I like going outside for my job.

I've been doing this project of Earth's ancient climate now for my three and a half years of graduate school. I also did a somewhat similar project over my last year of college for my senior thesis.

Carbon dioxide (CO₂) and methane do absorb/scatter infrared light very efficiently, due to their molecular rotational and vibrational energy transitions. And if greenhouse gas concentrations continue to rise then average global temperatures will continue to rise as well. Hence the importance to reduce our greenhouse gas emissions.

FULL QUESTION: Regarding the causative agents for past "Snowball Earth Events" and recovery from them, I would think there must be an interplay between Milankovitch cycles, plate tectonic events (for instance, latitudinal locations of land masses, resultant ocean current patterns, prevalence or absence of large igneous province events, erosion and resultant effect on oceanic and atmospheric geochemical cycles), biotic evolution (especially oxygen levels) and probably significant factors I've not mentioned. Is there a "common denominator?"

There is certainly an interplay between all these factors for causing Snowball Earth events. I would say our current thought is that the positioning of continents and large igneous province events (for weathering and albedo) are the main driving forces for triggering the Snowball Earth events during the Neoproterozoic (the age my rocks are). But biotic evolution is potentially an important factor as well, and is seen as the main driving force for the Great Oxidation Event (GOE) Snowball Earth periods during the Paleoproterozoic.

Volcanoes! They keep pumping out CO2 to warm the Earth when everything else was covered in ice.

Great question! We do fly to get to Namibia, thankfully we are able keep most of the equipment (like rock hammers) in our checked baggage where they don't raise any issues.

I didn't give an exact number because it is still a hotly debated topic. Just the melting of all the ice probably took about 2–10 thousand years. However, the lingering after effects of the climate transition likely lasted tens of thousands to hundreds of thousands of years.