Archive for the ‘Anthropocene’ Category
The Geoscientist is the Fellowship magazine of the Geological Society of London. With the Permission of the Editor of the magazine, I hereby republish extracts from three items in the most recent issue (cover image shown here) of the magazine:
There will, no doubt, be howls of protest from all the ‘climate ostriches’ within the Geological Society – those who dispute the problematic nature of the reality that:
(a) the Earth’s fossil fuel resources are non-renewable and finite;
(b) burning them is the primary cause of ongoing climate disruption; and
(c) feeding 10 billion humans will be very hard without fossil fuels.
Sadly, however, reality is not altered by our refusal to face it!
(1) The Only Way is Ethics (Opinion piece by Roger Dunshea*)
We all know geology is the most enjoyable of sciences, bringing together a differential of maths, a wave of physics, a whiff of chemistry and a gene of biology… Our science combines analytical techniques in the laboratory with equally important observation, sampling and experimentation in the field… We grapple with the fundamental structures of this planet, its minerals and history, and the enormous magnitude of time it has taken us to get to where we are now. As a group of scientists we are in a unique position to appreciate that this planet’s rock-based economic resources are essentially finite and that their replacement is either not possible or may take at least mega-millennia…
These resources have delivered abundant power and materials, resulting in outstanding increases in agricultural and industrial output, as well as some glinting adornments for the celebs. The average lifespan of Homo sapiens has been transformed and global numbers have increased at an astounding rate…
Geologists specialise in different areas of the science… Geology has made a major contribution to global society but do we risk threatening the prospects of future generations due to the current unsustainable levels of extraction? Should geologists start thinking more about helping the long term economic prospects of Homo sapiens?
So while our peers in the medical and life sciences are developing new ethical standards to protect the wellbeing of current and future generations, is it not now time to start discussing and developing a set of geological scientific ethics that can support very long-term global economic sustainability?
(*Roger Dunshea spent most of his career in the UK public sector in managerial and financial roles)
(2) Experimenting on a Small Planet (by William Hay)
This thick and well-illustrated volume is a highly readable tour through the multidisciplinary science behind Earth’s oceanographic and atmospheric warming and cooling on both geologic and anthropogenic timescales, by a major contributor with a phenomenal grasp of the whole… Many of these topics are neglected in mainline global-warming work, and professionals as well as outsiders will find much that is new to them…
The decreasing temperature gradient south from the Arctic has already made the northern jet stream slower, more frequently erratic, and much more likely to stall in place with the weather masses it controls. Extreme weather is steadily increasing as a result, and more and worse would be coming even if greenhouse gas emissions stop immediately (which of course will not happen). Predicting the specific great changes in oceanic and atmospheric circulations is confounded, however, because there has been no documented past occurrence of an icy Antarctic and an ice-free Arctic from which to reason by analogy, and north-south interconnectedness is uncertain, nor has there been anything comparable to our geologically instantaneous increase of greenhouse gasses to levels unknown for 35 million years.
Bill Hay has searched for explanations of the two major stable states of Phanerozoic climates, “greenhouse” and subordinate “icehouse”, and of the switches between them. He has focused on the Cretaceous and early Paleogene, when the poles were mild and temperate and deep oceans were warm, and the middle and late Cenozoic, when Antarctic continental ice and a mostly-frozen Arctic Ocean produced strikingly different regimes because the world’s oceans were dominated by polar-chilled deep water, and the atmosphere by great latitudinal temperature and pressure gradients, a regime that culminated in the waxing and waning continental ice sheets of the past two million years.
Changes due to even ‘present’ atmospheric CO2 levels would continue to develop for millennia before new quasi-equilibria were established. Mankind is facing catastrophe as a rapidly increasing population simultaneously outgrows its resources and enters a more hostile global environment.
(Review by Warren Hamilton)
(3) The Energy of Nations (by Jeremy Leggett)
Subtitled ‘Risk Blindness and the Road to Renaissance’, the risk that Leggett’s book draws to our attention is that because of the demands of nations for us collectively to cut back on the use of fossil fuels (so as to mitigate the effects of global warming caused by emissions of carbon dioxide) eventually the assets that oil companies have in the ground, and that form the basis for their share price, will become worthless because we shall have to stop using them…
“This risk goes completely unrecognised by all sectors of the financial chain” he says. If that realisation comes suddenly rather than slowly, it could “amount to another bubble bursting and a grave shock to the global financial system”. We are looking at what Leggett calls “unburnable carbon”.
Leggett’s argument also revolves around ‘peak oil’. Production has been running at about 82 million barrels/day, but the rise in demand by 2050 will be such that we will need 110 million Bpd. Yet all that industry has been able to do over the past few years is keep production flat in a time of extended oil prices. Where is all that extra production to come from?…
Leggett’s answer is to call for massive investment in what he calls the cleantech energy sources we shall need in the future. Currently we are saddled with a dysfunctional dinosaur and riddled with short-term thinking. The industry may be right to say there will always be gas, and oil, and coal. But the Stone Age didn’t stop because we ran out of stones. Endless growth is a problem on one planet with finite resources. So what can we do about it? We could all start by reading Leggett for ideas, that’s for sure.
(Review by Colin Summerhayes)
Copyright in all of the above remains with Geoscientist.
Must the World Bank now be added to the supposed list of environmentally-alarmist institutions seeking to use the perceived threat of climate change as a pretext for imposing global authoritarian government via the United Nations? This is essentially the position of all those that dispute the reality of the 97% scientific consensus – or the IPCC’s 95% confidence – that humans are the primary cause of the climate change we are now witnessing.
Unfortunately for such conspiracy theorists, the truth of the matter is much more unpleasant: Climate scientists are not engaged in a global conspiracy to provide the UN with an excuse to subvert the power of national governments. Conspiracy or not, it would be bad enough if our national governments had spent the last 25 years ignoring the warnings of climate scientists. However, the truth of the matter is even more insidious: The IPCC has spent the last 20 years or so compiling reports detailing the nature, scale and urgency of the problem we face, only to have our national governments systematically neuter their reports and ignore the warnings they contained.
Similarly, it seems, our national governments appear determined to ignore warnings from professional bodies, national scientific academies, and international organisations. Anyone who asserts that humanity needs to stop burning fossil fuels as fast as possible is, it seems, immediately dismissed as an environmental ‘alarmist’.
If you stop to think about it objectively, even for a moment, the reasons for this are very obvious: Far more serious even than the USA defaulting on its debt repayments, the problem is that the share prices of the World’s fossil fuel companies are entirely dependent upon the assumption that all the Earth’s fossil fuels will be burned. This is referred to as ‘business as usual’ (BAU).
Thus, in the minds of our politicians at least, if they accept the reality that we have a problem at all, the only solution to the problem is one that allows fossil fuel companies to continue with BAU.
Unfortunately for our politicians, fossil fuel companies, and all life on Earth (human and non-human), such a solution does not exist and is, almost certainly, technologically unachievable in the timescale that it would now be required.
The solution everyone is hoping will emerge is carbon capture and storage (CCS). This is a subject about which I have written a great deal; and I do not intend to repeat myself now other than to say this: CCS will only be able to help solve our problem when the rate of removal of CO2 from our atmosphere is greater than global emissions. Getting CCS to work will take decades (as will decarbonising our economies). It is quite possible that we do not have decades of time in which to do either but, one thing is for sure, it makes no sense to delay making a serious attempt to do either.
Therefore, I believe all would do well to ponder the question as to why the World Bank published ‘Inclusive Green Growth: The Pathway to Sustainable Development’ last year. There is a big clue given in the ‘Abstract‘, which reads as follows:
Economic development during the next two decades cannot mirror the previous two: poverty reduction remains urgent but growth and equity can be pursued without relying on policies and practices that foul the air, water, and land.
The World Bank accepts that humanity cannot go on treating the Earth with contempt; treating it as if both its resources and regenerative capacity are infinite. This is because, as is becoming increasingly obvious (in the case of the latter at least), they are not infinite.
This brings us to the crux of this post, which is to refute the entirely bogus argument that we humans have nothing to be afraid of because climate change is natural; life has survived it in the past; and will therefore do so again. There are at least two problems with this line of argument:
1. Because we were already in a warm interglacial period – and atmospheric CO2 is now 40% higher than at any time in the last 1 million years – it is highly unreasonable to dispute the fact that post-Industrial warming is unnatural (i.e. all sparrows may be birds but not all birds are sparrows).
2. In the entirety of Earth history, there have been 5 mass extinction events (i.e. periods when between 50 and 95% of all species have been wiped out). These events are each associated with periods when global average temperatures were more than 5 Celsius warmer than they are now (and there is strong evidence that a sixth mass extinction is already underway).
In responding to sensible comments on my previous post, ‘A summary of the ‘Climate Departure’ research of Mora et al.‘, I found myself referring to the most recent mass extinction event in the Earth’s history, the so-called Palaeocene-Eocene Thermal Maximum (PETM), which occurred 55 million years before present (MaBP). However, as the following video graphically demonstrates, what is now happening to the Earth’s climate as a result of the post-Industrial burning of fossil fuels, is looking increasingly like the Permian mass extinction event, which occurred 252 MaBP.
This video is only about 10 minutes long, so I hope people will watch it. If not, however, the main points are summarised below:
1. There have been five mass extinctions before and humans are now almost certainly causing a sixth.
2. The ongoing melting of terrestrial ice will now cause sea level to rise continuously for several centuries.
3. This is probably unstoppable but is survivable (i.e. assuming all humans can move away from coastal areas).
4. All past mass extinction events occurred when global average temperatures > 5 Celsius warmer than now.
5. Common to each event is further rapid warming triggered by methane release from permafrost and seabed.
6. We already have evidence that rates of both species extinction and methane release are now accelerating.
7. Positive feedback mechanisms (such as disappearing sea ice) will soon make methane release unstoppable.
8. If this ‘tipping point’ is passed, anthropogenic climate disruption will almost certainly be unsurvivable.
This is why the World Bank agrees that we need to decarbonise our global economies as fast as possible.
The video below contains a very compelling 22-minute summary of an impressive array of work, widely reported in the World’s newspapers this week. The research team, based in the Geography Department at the University of Hawaii, was led by Associate Professor Camilo Mora.
Sadly, it has already been dismissed by people with a track-record denying, downplaying or dismissing the nature, scale and urgency of the problem of anthropogenic climate disruption (ACD). People such as Bjorn Lomborg, for example.
A brief summary of the key points of the research:
1. For any geographic location the time of ‘climate departure’ is the time beyond which even the coldest monthly average temperature will be warmer than anything observed in the last 150 years. The same method was used to determine the time beyond which a range of other factors (such as precipitation and evaporation) would no longer fall below the range of local values observed in the last 150 years.
2. The monthly average data for all these calculations, data were obtained from 39 global climate models (GCMs – the accuracy of which I discuss below) constructed by 21 climate modelling centres in 12 different countries around the World. Common to all of these models is the same suite of CO2 emissions projections scenarios, two of which the research team used to define the range of possible temperature rises: RCP8.5 – representing a business as usual (BAU) scenario where humanity makes no attempt to reduce CO2 emissions; and RCP4.5 – representing a scenario where globally co-ordinated and concerted efforts are made to reduce CO2 emissions. With regard to atmospheric CO2 concentrations, it should be noted that:
— RCP8.5 is projected to result in a continuing increase to 900 ppm CO2 by the end of the Century; and
— RCP4.5 is projected to result in a peak value of 500 ppm being reached by mid-Century.
3. The results suggest that on average, climate departure (for temperature) is reached 2047 under the RCP8.5 scenario, or 2069 under the RCP4.5 scenario. This therefore implies that aggressive attempts to reduce carbon emissions could delay the onset of climate departure by several decades. Furthermore, the results suggest that climate departure will come to lower latitudes (equatorial and tropical areas) first. Under RCP8.5 this is as early as 2020 in some places. Under RCP4.5, climate departure is projected to be experienced almost everywhere by the end of the Century.
4. The team has produced an interactive map, published online here by the Washington Post newspaper, which can be used to see when climate departure is predicted under both scenarios for any location on the Earth’s surface.
5. The team suggests that the historical focus on absolute changes in temperature (i.e. predicted and observed to be greatest in polar regions) have given humans a false sense of security about the likely personal impacts. This study inverts that pattern and shatters the illusion that humans will not be directly impacted by changes in temperature. This is because, where the natural climate variability is smallest, less absolute change is required for it to be significant and most of the species present have less resilience to that change.
6. The research highlights the changes that have already occurred. Indeed, the most striking finding of the research is that the pH of seawater across the entire planet – i.e. without any exceptions – is already lower than it has been at any time in the last 150 years.
7. The research highlights the fact that those areas that are likely to reach climate departure soonest are also areas with the highest average population density and the lowest capacity to adapt. Under RCP4.5, it is expected that 1 billion people will be living in area experiencing unprecedented climatic conditions by 2050. Whereas, under the RCP8.5 this is expected to be 5 billion people (i.e. half the currently-projected global population).
8. The research indicates that the Earth’s most significant biological assets (essential ecosystem services and biodiversity) are at risk. This is the consequence of three facets of the above: (a) equatorial and tropical regions will be the first to experience climate departure; (b) they contain the greatest proportion of the Earth’s biological assets; and (c) are the least resilient to any change and the least able to adapt.
Conclusions (some readers may find some sentences upsetting)
1. If we stick to BAU, we will guarantee that (a) the long-term consequences will be increasingly unpleasant; (b) mitigation will become impossible; and (c) adaptation will be required sooner and faster and therefore be more costly. Alternatively, if we decide to try and mitigate ACD (by aggressively reducing CO2 emissions), we may be able to limit the unpleasantness and the scale and total cost of adaptation required (by humans and non-humans alike).
2. If we do nothing, the extinction of a significant proportion of species on Earth would appear to be unavoidable in the long-term (and, if that happens, the survival of humanity would have to be seriously in jeopardy). Alternatively, if we take action, the extinction of some species looks highly probable but, critically, this will buy most species several decades to adapt. This means that the costs of adaptation can be spread over those extra decades.
3. Given all of the above, how can it make any sense to continue to argue about what we should do?
Comments about the accuracy of Global Climate Models (GCMs)
One very easy way to dismiss all this is to point out that, in the course of the last decade, global average temperatures have slipped from well above 75th to just above 5th percentile of GCM predictions. Despite this, however, the exponential nature of the observed temperature increase over the last 150 years is very obvious in the above video.
Furthermore, the only way anyone can justify reaching the conclusion that this increase will not continue is by asserting that CO2 is not the main driver. A recent article on the Yale Forum on Climate Change and the Media website, entitled ‘Examining the Recent Slow-Down in Global Warming‘, has an excellent set of graphs that explain how and why we can be certain that CO2 is the main driver.
In addition, as per the comments I have posted on the above article, none of the GCMs include the global dimming effects of industrial pollution. Given that this is the case, I really do not understand why so many climate scientists keep saying we do not understand the reason for the current hiatus. In his book, ‘Storms of my Grandchildren’, James Hansen repeatedly complains about the fact that, 20 years ago, NASA refused to invest in satellite monitoring of this pollution. Thus we have been unable to model its effects because we have no data to put into the GCMs.
I decided that my review of The Revenge of Gaia, as published by James Lovelock in 2006, was dragging on a bit, so have decided to finish it off. This is therefore the fourth and final part (and thus longer than normal posts).
Having explained what Gaia is (part one), discussed the need to decarbonise our economies (part two), and discussed the various sources of renewable energy available to us (part three), we must now confront ‘the radiating face of Gaia’. The possibly surprising reality is that almost half the book is taken up by Lovelock discussing the sensibility – if not inevitability – of the widespread use of nuclear energy to generate electricity.
As before, some may consider this a self-contradictory position to adopt because, as indeed Lovelock concedes, the ecological carrying capacity of the Earth in a post-carbon age is unlikely to be greater than it was before the Industrial Revolution. That being the case, why would such a small population (of say one billion humans) need nuclear energy; and who is to say they would be capable of harnessing it? When the history of human failure (to see the writing on the wall) has finally been written, catalogued and left in the library long enough to be coated in dust, some may well wonder if today’s nuclear power plants will become the curious prehistoric monuments of a distant, post-carbon, future.
However, I see Lovelock’s pro-nuclear stance as part of the technological optimist side of his split personality: Whereas his pessimistic side laments the unintended ecocide being caused by human arrogance, greed and stupidity; the optimistic side of Lovelock assumes humanity will somehow avert the approaching environmental catastrophe and will, therefore, need lots of energy to power a post-carbon civilisation.
However, to be fair, Lovelock has always been in favour of nuclear energy. In this respect, he is probably very unusual amongst those concerned with issue of environment degradation. He may never have quite been a lone voice crying in the wilderness, but the truth of the matter is that most pro-nuclear environmentalists have not always thought as they do now (e.g. Mark Lynas and George Monbiot). Nevertheless, however and whenever they came to be so, they join with the likes of Tom Blees, Stewart Brand and James Hansen – in being pro-nuclear. Personally, I think it is much more accurate to describe them as ‘ecopragmatists’ (and would count myself as one too). Indeed, Brand’s most recent book sounds like it is worth reading: Whole Earth Discipline: An Ecopragmatist Manifesto.
As such, all would agree that nuclear energy will have to be the main source of power in decades to come if billions of humans survive the approaching environmental meltdown, which we are causing by burning fossil fuels.
Before continuing, I think it is worth drawing attention to a couple of things recorded by Brand in the online Afterword he is maintaining in relation to this book. (i.e. as quoted on the Wikipedia page for the book – as per the above link):
(1) Brand quotes Lovelock as having repudiated his alarmism because “Something unknown appears to be slowing down the rate of global warming”. This would appear to suggest that Lovelock was not satisfied by the answers that climate scientists have given, namely that: (a) warming is being offset by ‘global dimming’ (caused by other forms of atmospheric pollution); and (b) the ‘missing’ heat will be found in the deep ocean (because it must have gone somewhere).
(2) Brand has appears to admit having been influenced by the ‘global warming has stopped’ myth that has been peddled so fiercely by the fossil fuel lobby. He has therefore suggested that maybe nothing (more) will happen as a result of the accumulating greenhouse gases. However, he also chose to add that doing nothing about our CO2 emissions would be “like playing Russian Roulette with five cylinders loaded”.
As I have now said quite a few times, although sympathetic to the overall message, I am concerned by intellectual incoherence, selective blindness and a tendency to exaggerate, which Lovelock appears to display in the writing of The Revenge of Gaia. Although not limited to his remarks about radiation and nuclear power, these traits are certainly very much present. This is a shame, in my view, because Lovelock also makes some very valid points about the irrational way most people assess the chances of either good or bad things happening. For example, the chances of any individual winning a lottery is extremely small but, even so, a great many people waste an awful lot of money trying to do so. Similarly, the risk of any individual dying as a result of travelling in a car is much higher than that of flying in an aeroplane but, even so, how many of us worry about the former more than the latter?
Lovelock, correctly in my view, blames widespread anti nuclear sentiment today on fears, stoked by the Campaign for Nuclear Disarmament (CND), over mutually assured destruction that grew out of the insanity of the Cold War. Such fears were entirely justified but, as Lovelock says, the demonisation of the civil nuclear power industry was not. Just because it was a by-product of military programmes to build atomic bombs does not make it inherently bad. Mobile Phones were a product of military surveillance technology, but they are generally accepted as being beneficial (apart from those who blame them for killing bees and causing brain cancers).
Cancer is another subject about which Lovelock has a lot to say; but here also, I think he takes his argument too far. It is undoubtedly true that cancer is very common; that very little of it is caused by radiation; and that even less is caused by artificially-created radiation. Lovelock makes the point that the whole planet was irradiated as a result of atomic bomb tests in the 1950s but the only deaths linked to such tests have been among those who witnessed them. Lovelock also recalls the reactor fire at Windscale (now called Sellafield), which also irradiated the entire UK but has not been linked to any deaths. Most famously of all, of course, Lovelock cites the meltdown at the Chernobyl plant in what is now Ukraine. Estimates vary but, given the amount of hysteria caused in Europe about radiation clouds, the numbers of people killed as a result (i.e. as determined how many more people have died than might otherwise be expected to die) is really not that great. This is not intended to belittle the suffering of individuals; merely to suggest that people put these things in some proper perspective: Perspective that might include considering how many people are shot dead every day; or die in car accidents every year; or how many were killed in wars in the last decade; or died as a result of the Spanish Flu epidemic nearly 100 years ago.
However, Lovelock goes further; and the point at which I think he ceases to be reasonable is this: He suggests that oxygen is a carcinogen. Noting that – whereas some photosynthesising plants can live for hundreds of years – humans tend not to live for much more than 100 years, he argues that oxygen is a carcinogen because it of its involvement in biochemical processes at the level of individual cells (i.e. respiration). This may be true but, if so, it would also be true to say that eating causes constipation. However, that does not mean that we should be worried about eating! Furthermore, there are also scientific studies that have linked the development of cancer with oxygen-deficiency at cellular level. Far more importantly still, there is a great deal of evidence to suggest that the risks of any individual dying of cancer are dramatically increased by their inherited DNA and lifestyle choices they make (such as excessive alcohol consumption or tobacco smoking). For all of these reasons, I find Lovelock’s argument about oxygen being carcinogenic to be misleading; if not disingenuous.
Nevertheless, I agree with Lovelock that civil nuclear power should not be feared in the way it is (in many minds); and it should not have been abandoned in the way it has (in many countries). However, I remain bemused by the conflict between Lovelock’s misanthropic pessimism (most recently echoed by Bob Geldof) and his technological optimism, which ignores the geologically unprecedented rate of both CO2 rise and warming that has occurred in the last 200 years.
In addition, there remains the problem that the global use of civil nuclear power would likely be a new form of technological dependency (along with the widespread use of GMOs) that will probably not reduce inequality of opportunity because the ‘trickle-down’ effect does not seem to work.
There is also growing evidence that time is no longer a luxury that humanity has. The relatively stable sea level and climate that has made agriculture, civilisation, urbanisation and modernity possible has now been brought to an end by the folly of humans believing they were superior to nature; rather than part of it.
We have fouled our own nest; and we appear to be running out of time to clean it up.
Greenland was never called Iceland – even though it is largely surrounded by the ice cap and covered in glaciers. Iceland, which often has brilliantly green places, is also in the Arctic Circle. But Iceland is not connected to the rest of the Arctic sea ice.
The Arctic can be confusing. But it’s needs protection. If you have not already done so, please sign up to save the Arctic, before big oil risks it all for profit, by visiting: www.savethearctic.org.
For the avoidance of any doubt:
According to the 12th Century oral history “Landnámabók”, Iceland got its modern name from the Norwegian Viking Flóki Vilgerðarson when he saw a distant fjord full of sea-ice from a tall mountain.
In the “Icelandic Sagas”, Erik the Red, a Norwegian-born Icelander was exiled for murder. He sailed away to Greenland and supposedly gave it a pleasant name to attract more settlers.
Confusion may be understandable but ideological blindness is unforgivable. Increasingly obvious climate disruption will not stop until we make serious attempts to stop causing it. Effectively irreversible, it will soon be unstoppable. End of story (in more ways than one).
Can someone please explain why…
Arctic ice is still disappearing.
Biodiversity is still reducing.
Coral reefs are still dying.
Deserts are still growing.
Experts are still worrying.
Fisheries are still shrinking.
Glaciers are still retreating.
Heatwaves are still coming.
Ice caps are still melting.
Jungles are still burning.
Koch Brothers are still lobbying.
Lindzen is still obfuscating.
Micheal Mann is still winning.
Non-experts are still losing.
Oceans are still expanding.
Positive feedbacks are still emerging.
Quackery is still appealing.
Risks are still increasing.
Sea levels are still rising.
Temperature records are still breaking.
Uncertainties are still reducing.
Vanuatu is still sinking.
W, X, Y and Z are still missing.
See here for more on spoof book cover.
If the link between geology, plate tectonics, and climate change seems obscure to you, I would recommend reading the whole thing. However, if you’re busy, let me jump straight to the important bit – what I see as being the implications for humanity today:
Just because it has been much warmer in Earth’s distant past does not change the facts that:
(1) All life on Earth is adapted to the relative climate stability that preceded the Industrial Revolution; and
(2) Most life on Earth will not adapt to the unnatural change now underway unless we stop causing it.
Now we know we are in a hole, I think it would be a good idea to stop digging.
For those who think they might have some time to spare, here is how the article begins:
This post delves into the long-term carbon cycle that involves the interactions of the atmosphere with rocks and oceans over many millions of years. Because of its length, I’ve broken it up into bookmarked sections for easy reference: to come back here click on ‘back to contents’ in each instance.
Introduction: what is weathering?
Carbon dioxide and rock weathering: the chemistry.
Limitations to the precipitation of calcium carbonate: the Carbonate Compensation Depth.
The significance of weathering as a carbon-sink.
Deep weathering of rocks: an illustrated example from Mid-Wales, UK.
How breaking up minerals affects their weathering-rate: mountain-building as an accelerant.
Picking up signals of major weathering episodes in the geological record.
If this sounds interesting, I hope you will go and read the whole thing: