Reading Time: lots, but hopefully worth it. Sound bites are generally not worth reading.

When is a risk not a risk?

Earlier this year, Exxon was in the news for the usual wrong reasons – as an oil company they were accused by various Californian, and other, municipalities of being directly responsible for the threat of flooding that these coastal municipalities were in danger of, due to global fossil-fuel originated climate-change.  

This kind of action by state and regional level administrations actually has an impressive list of victories; several of which appear in Netflix’s Dirty Money series. So, any commentary herein is caveated by the stellar track-record. Notwithstanding this, the action against Exxon is a worrying trait as it expressly compares the oil companies with the tobacco companies of the last decade(s).  This is an important point, as it is an attractive narrative, but also misses the point that our techno-industrial society doesn’t need cigarettes, but does need cheap energy. Whilst this is an interesting avenue to explore I’ll resist the temptation today.

However, before getting back to Big Oil’s climate change research, a quick detour into Bond space. This particular legal confrontation has a nice twist. Many of these same municipalities have recently issue municipal bonds. Anyone who has ever been near a bond issuance will know that a big part of the documentation concerns Representations and Warranties about “risks”.  Clearly if you are a coastal community and you believe that climate change is real and measurable enough to sue Exxon for causing it, you should definitely detail this existential risk to your potential bond holders. 

San Mateo County’s complaint says it is “particularly vulnerable to sea level rise” and that there is a 93% chance the county experiences a “devastating” flood before 2050.

If you didn’t outline the risk, you either don’t think it is sufficiently real to be worth mentioning, or you are misleading your future bond holders. 

However, bond offerings in 2014 and 2016 noted that the county “is unable to predict whether sea-level rise or other impacts of climate change or flooding from a major storm will occur.”


Exxon’s lawyers have countered the litigation along these lines – and it will be interesting to watch; although this is just one case in a barrage against Big Oil – many of which have more compelling arguements about the double standards of internal research and public positioning.

Exxon’s not-so-secret Climate Change research revealed

Shock-horror. Not only has Exxon done climate change research, it is actually a pioneer in this field.  Not that this is a secret.  In 2005, the Exxon scientist Peter Vail was awarded the Benjamin Franklin Medal in Earth and Environmental Science for his work done in the 1960s (published in the mid 1970s) on global sea level change.

This work developed the concept of sequence stratigraphy, a technique for interpreting large scale geological features like deltas, preserved (or indeed absent) in the sedimentary record. Advances in the acquisition of seismic data and processing, combined with the global coverage that only a massive oil company like Exxon had, enabled Vail and his co-workers to see the big picture.

 Using these data the group was documenting and interpreting large-scale, basin-wide depositional patterns, stratal configurations, and unconformities in basins around the world. They proposed a chronology of global sea-level fluctuation as a framework for global correlation, resulting in a  world sea-level curve. This further led to a new eustatic sea-level model.

Whilst this is now part and parcel of geological knowledge, at the time this was pretty revolutionary stuff Indeed we should note that plate-tectonics only became part of the mainstream in the late 1960s, about the time the USA was landing men on the moon, so world-wide sea-level changes were also quite revolutionary.

Vail and colleagues proposed a chronology of global sea-level fluctuation as a framework for global correlation, resulting in a world sea-level curve. This was hard to comprehend even for geologists used to working with huge time scales. In essence what was described were truely enormous changes in relative sea-level that could be correlated around the globe. The most obvious evidence of this were the vast prograding and retrograding delta systems seen in the seismic views of the geological record. As sea-level drops so deltas advance (prograde) into the space left.

Conversely as sea-level rises so deltas are pushed back (or eroded completely). About 15 years ago I saw a vast 2D seismic line covering nearly 800km across Siberia – and all you could see were hundreds of prograding clinoforms stepping out into the cratonic basin (although in this case more due to basin subsidence than sea-level change).

What was remarkable about Vail’s (and subsequent) work was the shear scale of the sea-level changes evidenced by the data. Global sea-level change was not measured in mm or cm or meters, but in 10s and 100s of meters. These numbers seem hard to comprehend when compared to human experience, but are now universally accepeted in the scientific community. source

It is clear that such huge changes have occurred over millions of years, and as such have limited relevance to the debate on anthropogenic climate change – although if you look at the volatility of the data you can see that some major changes have happened in relatively short geological periods. The nature of geological data is such that we will not be able to identify time-scales that are relevant – so “relatively short geological periods” is also of limited relevance. Studies of more recent fluctuations (middle Stone Age) via archaeological data as well as more detailed ice cores show that natural changes can occur very fast.

The team identified two episodes of extreme cooling which saw average temperatures drop by more than 3 degrees in the space of a decade. The first of these events occurred very early after humans began to return to the area after the last ice age.

Some of the more recent smaller fluctuations due to recent glacial events have had changes of 10s of meters. The coastal area around Santa Cruz has very distinct raised beaches (actually paleo beaches exposed by sea-level dropping). The lowest terrace is about 100,000 years old, and the second terrace is about 230,000 years old. The third stair step (on Wilder Ranch) is about 350,000 years old, and the fourth, also exposed on Wilder, about 490,000 years old. source

In the above you can clearly see three paleo-surfaces.

Massive sea-level change is a natural phenomenon. Rapid changes in climate also pre-date the industrial revolution. The modern problem of course is that whether anthropogenic or not, any variation in sea-level will badly impact millions and millions of people.

When I was at school (as noted in previous posts – this was in the Jurassic), the big scare was that “the next ice age” was just around the corner. This has some basis in logic, given that the last 5000 years has been unusually warm and unusually stable – maybe the single biggest cause of the rise of civilisations over this period (its the extreme right-hand part of this chart from 0 to the first tick-mark (which is -10,000))

A statistical regression to the mean would indicate more cold ahead. Some even suggest a bit of global warming could just delay the next ice age. The problem with this is that the climate is a massively complex system and not all feed-back loops are well understood (despite the “unanimity” of the most ardent). The AMOC (Atlantic Meridional Overturning Circulation) is maybe the most scary. Massive influx of fresh water from melting Greenland and Arctic ice alter the salinity equilibrium in this system. The circulation depends a lot on density contrasts in part due to the salinity (thermohaline circulation); it is suspected that this has a critical equilibrium. When the tipping-point is passed, the circulation can shut down – leading to a halt in the movement of warm equatorial waters to the north (the Gulf Stream). It is thought that thermohaline shutdown in the North Atlantic may have been the cause of previous ice ages that saw hundreds of meters of ice covering northern Europe. And guess what? When it happens, it happens fast. OK, not as fast as depicted in the disaster (of a) movie The Day after Tomorrow, but in a time frame of years to decades. So that may be in part why we hear about “climate change” not “global warming” so much these days.

So back to Exxon’s not-so-secret climate change research – remember those sea-level curves wildly fluctuating over -100m to +250m ? well I’ll just leave you with the IPCC projects for the next 100 years. The scale is in m. Not saying it won’t be bad, but it could be a lot worse.