16 January 2017

Climate Change - Is It Real?

Repeatedly I have had questions about climate change addressed to me, both electronically in USGS Ask-A-Geologist queries, and verbally from acquaintances  There are a lot of things floating around in the news media about climate change. A lot of this is correct, some of it is foo-foo, and far too much of it is deliberate obfuscation by people who have a self-serving financial agenda. 

Sadly, there are scientists who sell their souls to corporations (whether Big Carbon, Big Pharma, or Big Tobacco), but we will not go there...

Q: Is climate change real, is is this some liberal Mother Earth Tree Hugger thing going on?

A: A short summary of what's going on:

1. Virtually all climate specialists not paid by Big Oil agree that the Greenhouse Effect is real. In fact, it was first reported in the scientific literature by Joseph Fourier (of Fourier transform fame) in 1824. It's been tested and proven repeatedly ever since.

2. There is a lot of yearly and decadal variability in climate data. Anyone can cherry-pick the weather data to prove any point they want to - including waving a snow-ball in a Senate hearing - but that's not science. If someone is trying to convince you that climate change is not happening, ask yourself: who's paying this guy?

3. CO2 in the Earth's atmosphere has gone from 315 ppm in 1958 to over 400 ppm today (Mauna Loa observatory). Virtually all scientists with integrity accept that most if not all of this change is due to human activity. The reason? The change has been accelerating (second derivative is positive) since about 1850, when the industrial revolution really got underway. By second derivative being positive, I mean that it is ramping up faster and faster as time progresses. This is the well-known "hockey stick" graph made famous by Al Gore. 

4. Is the increase in CO2 human-caused? If we look at the carbon isotopes in this increased atmospheric CO2, we can show that it is definitely caused by fossil fuel burning. Carbon-14 is a radioactive isotope with a half-life of 5,730 years. There is a certain amount in the atmosphere and living plants from cosmic rays transforming nitrogen in the upper atmosphere - this is well-calibrated by many studies. With a half-life this short, if something bearing carbon is buried and put out of reach of the atmosphere, the carbon-14 drops below measurable levels by 50,000 years. Fossil fuels thus have NO carbon-14 in them. Burned, these fossil carbon sources contribute only carbon-12 and carbon-13 to the atmosphere. It's not hard to calculate how much fossil carbon has been burned: about 300 billion tons since 1800 AD. It's also not hard to measure the levels of carbon-14, the radioactive isotope, in the atmosphere over the past two centuries: it's sequestered in tree-rings and other places where it can be measured, year by year. Human involvement in the growth of CO2 in the atmosphere is proven by the steady drop of carbon-14 levels in the atmosphere since 1800.  

5. The last time the atmospheric CO2 reached this 400 ppm level, according to the geologic record, was during the Pliocene (5.3 to 1.8 million years ago). At that time, about half of Florida was underwater (including the places where ~80% of Florida's population now lives). I've pulled Pliocene marine fossils (sharks' teeth and echinoderms) out of land deposits in central Florida with my own hands; they are on my bookshelf.

6. There is a latency of CO2 after it gets into the atmosphere, and some scientists calculate this to be about 30 years. Translation: it tends to stay there. The oil you burn today will really be impacting your kids 30 years later. 

7. A gallon of gasoline, which weighs 3 kg, will produce about 10 kg of CO2. The extra mass comes from the oxygen you might want to breathe instead. That gallon translates to 50 kilometers traveled in my car. And that's not counting the CO2 generated to extract and refine the gasoline. The Energy Returned on Energy Invested for Athabascan tar sands is between 4 and 7. Translation: a rather huge amount of energy is used up just getting the bitumen into the form of gasoline. 

8. Nearly 5 billion impoverished people on Earth want to have a high-protein lifestyle like their grandparents could not have even dreamed of. This means vastly-increased herds of vegetation-eating, meat-producing animals. The amount of methane a cow produces is truly breath-taking (pun intended): up to 500 liters of methane a DAY. That's more than a 5-drawer file cabinet. Methane is 37 times more potent than CO2 as a Greenhouse Gas for capturing solar heat. That pushes it up beyond the volume of my office in CO2 equivalent - in one day. One normal, flatulent cow.

9. Increased temperatures mean more glacier calving, and more melting of Arctic, Antarctic, and Greenland ice caps, which are collapsing at truly stunning rates - and the collapse accelerating. Less ice on the ground and on the polar oceans means that the darker - light-and-heat-absorbing - under-layers will be exposed, trapping yet more solar heat and making the inevitable change non-linear. Translation: these changes are accelerating with time. 

10. Nine of the ten hottest years in now-centuries-old records have happened in the 21st Century. 2016 was the hottest year, globally, ever.

It's not hard to draw some conclusions from all this:

1. Do NOT buy beach-front property, Anywhere.

2. Move to the Pacific Northwest, or the Canadian prairie provinces. They will be among the very few winners of climate change. 

There are still several unresolved questions:

1. How FAST?
How quickly will the global climate change consequences befall us? The current speed of change has never happened before, as far as geologists can tell, in Earth's history. Ever. Predicting our future depends on climate modeling, and these models are fraught with assumptions and disagreements. However, they are beginning to coalesce, and they are now in general agreement. 

2. How BAD?
Likely consequences include (but these cannot be easily quantified):

  • Sealevel rise... and because of tectonic settling this will be worse on the east coast of the U.S. This means more, far-reaching devastation from storms like Katrina and Sandy are in our future.
  • We can expect bigger and more devastating hurricanes and tornadoes. If seawater rises and hurricanes grow in average size, then the storm surges they drag with them will reach deeper and deeper into the continental interiors. About 80% of humanity now lives within 100 km of a seashore.
  • Greater and more terrible droughts and wildfires can be expected. Because of well-intended but ultimately catastrophic wildfire suppression policies over the past century, these fires will become truly terrible in the continental U.S., Russia, and Brazil.
  • A consequence of droughts and wildfires: massive disruption in the world's food supplies.
  • We are already seeing the sixth mass extinction of animal life - and explosions of other destructive types of life (e.g., jellyfish, toxic algae). The current mass extinction of wildlife (habitat destruction and over-hunting) is comparable to what the Chicxulub asteroid did 66 millions years ago.
  • We are already seeing acidification of the oceans, with consequent dissolution and destruction of coral reefs, a major host of biodiversity - and the world's protein supply. The Great Barrier Reef of Australia is catastrophically collapsing as I write this.

3. Is it already beyond our control?
The question arises: are we already at the "tipping point"? The effect of climate warming on gas hydrates (methane clathrates) that lie beneath the continental shelves is a HUGE unknown. Most estimates (from seismic reflection data) suggest that these clathrates are many orders of magnitude greater than all other known hydrocarbon reserves (coal. oil, gas) on Earth combined. Gas hydrates are methane trapped in water ice below about 300 meters of seawater. This is the depth where pressure and cold ocean-floor temperatures currently trap them - where they remain stable. These methane hydrates have accumulated over millions of years from dying sea-life that drops to the ocean floor (some may derive from oil and gas deposits below the sea-floor sediments). A single cubic meter of these "gelids" can produce up to 180 cubic meters of methane - the internet is replete with photos of "ice" that is burning. A crucial unknown: will attempts to extract this stuff "open the doors" to a catastrophic release of vast quantities of methane into the atmosphere? 

The gas hydrates/methane clathrates issue leads to inevitable questions about non-linearity in climate forcing - and tipping-points. In other words, can things get out of control? Is it already too late - will we see a runaway temperature rise? Will we see inundation of most of the world's great cities (a real Waterworld)?

The geologic record suggests it may very well be too late - it's happened before for natural reasons - but the geologic record also shows that the Pliocene warm period came on far more slowly than what we are seeing in our modern world climate: it took hundreds of thousands of years to raise CO2 levels then - something that humanity has accomplished in just the past half century.

We are already in unknown territory, and precise predictions are probably not going to be correct.