FODI: We Are The Asteroid

Speaker: Elizabeth Kolbert

Setting out to talk about her recently published book, “The 6th Extinction”, Kolbert takes the auditorium on an abridged journey through the nexus of anthropological factors right this moment leading to a massive loss of biodiversity, and perhaps offering justification to the argument among geologists in favour of proclaiming our current geological era or epoch as the Anthropocene, a period where human forces take over from natural forces as the dominant force shaping our planet.

Starting with a case study of the extinction of the Hawaiian Crow, Kolbert begins to lay the groundwork for a much needed discussion of the myriad of interrelated human activities that are driving these very radical and rapid global changes. In the case of the Crow specifically, those activities resulting in habitat loss, the introduction of foreign invasive species, and the transportation of diseases via human activity. Kolbert also explores some of the lengths we’re going to in attempting to fix the symptoms by preventing extinction, including an amusing example of extracting male Crow DNA, and also suggesting, perhaps outside of the scientific community, we’re overlooking the broader causes.

Kolbert quotes Anthony Hallam and Paul Wignall, British paleontologists, defining ‘mass extinction’ as:
“Events that eliminate a significant portion of the world’s biota in a geologically insignificant amount of time,” then providing evidence of the last 5 mass extinction events, the last of which was 65million years ago when an asteroid collision wiped out the Dinosaurs.

Acknowledging there are many ways in which we are changing the world as drastically and almost as rapidly, in geological time, as an asteroid collision Kolbert explores the 3 she sees as most significant:

1. How We’re Changing The Atmosphere;
2. How We’re Changing The Oceans;
   and,
3. How We’re Changing The Principles of Geographic Distribution

1. ATMOSPHERE:

Each year human activity adds about 10 Billion Metric Tonnes of Carbon into the atmosphere with 7.2Billion people on the planet driving cars, lighting homes, heating and cooling, and consuming. We’re running geological history backwards by taking fossil fuels that took hundreds of millions of years to form in a process running in one direction, we’re then taking this process and reversing it in a matter of only one to two hundred years. CO2 according to ice core data has never been above 300ppm in the last 400,000 years, they are now at 400ppm and rising.

It is well known, and has been for a very long time, that CO2 traps heat in the atmosphere through the greenhouse effect, this heat is warming our air and our oceans, it is altering our weather patterns, and it is in a matter of decades destabilizing the climates that many plants and animals have evolved in over millions of years. Many cannot adapt to such sudden changes and face being wiped out in the coming mass extinction.

One Third of the carbon we’ve added to the atmosphere since the Industrial Revolution has been absorbed into the ocean, this leads to the second way we’re drastically changing the planet.

2. THE OCEANS

Carbon Dioxide in the air is very rapidly absorbed into the sea, when dissolved in water it converts the water to Carbonic Acid, this acidity in the water kills corals, starfish, shellfish, sea urchins, certain plankton such as Coccolithophores, and sends ripples through the food chain. Since the Industrial Revolution the oceans have absorbed about 150 Billion Metric Tonnes of man made CO2, every 4 hours the seas absorb another 1 Million Metric Tonnes of CO2, the net result is that the seas acidity has already increased around 30%.

3. GEOGRAPHIC DISTRIBUTION

The final point Kolbert touch on was one of particular relevance to Australia, we have lost more native mammal species than any other nation on earth, much of this due to habitat loss and competition from introduced species whose populations exploded due to a lack of native predators.

We move plants and animals around the world very intentionally for pets, agriculture and gardening. We also move species unintentionally, it’s estimated that everyday 10,000 species are being moved around the planet just in the ballast water of our tankers. These species are moved distances and across terrain they could never naturally travel across and this has perverse effects on the native flora and fauna as their lineage collide with the introduced species after millions of years of separate evolution, in effect creating “the new Pangaea” bringing the continents back together biologically.