anthropogenic global warming

A flood as an opportunity

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There’s a piece by Eric Holthaus, on Politico, that’s been doing the rounds on Twitter since yesterday. I’ll grant you it’s a powerful piece of writing, such as is necessary to cast Hurricane Harvey in what many would call the right light: as the face of climate change. One paragraph in particular I thought was particularly effective because it quickly but just as effectively explained how Harvey was a storm that’s been many years in the making, and how the intensity of rains it has brought to bear on Houston has been unusual even after accounting for the fact that the city has been battered by three once-in-500-years floods in the last few years.

Harvey is in a class by itself. By the time the storm leaves the region on Wednesday, an estimated 40 to 60 inches of rain will fall on parts of Houston. So much rain has fallen already that the National Weather Service had to add additional colors to its maps to account for the extreme totals. Harvey is infusing new meaning into meteorologists’ favorite superlatives: There are simply no words to describe what has happened in the past few days. In just the first three days since landfall, Harvey has already doubled Houston’s previous record for the wettest month in city history, set during the previous benchmark flood, Tropical Storm Allison in June 2001. For most of the Houston area, in a stable climate, a rainstorm like Harvey is not expected to happen more than once in a millennium.

In fact, Harvey is likely already the worst rainstorm in U.S. history. An initial analysis by John Nielsen-Gammon, the Texas state climatologist, compared Harvey’s rainfall intensity to the worst storms in the most downpour-prone region of the United States, the Gulf Coast. Harvey ranks at the top of the list, with a total rainwater output equivalent to 3.6 times the flow of the Mississippi River. (And this is likely an underestimate, because there’s still two days of rains left.) That much water – 20 trillion gallons over five days – is about one-sixth the volume of Lake Erie. According to a preliminary and informal estimate by disaster economist Kevin Simmons of Austin College, Harvey’s economic toll “will likely exceed Katrina”—the most expensive disaster in U.S. history. Harvey is now the benchmark disaster of record in the United States.

The pronounced “climate change is real” tone to the entire piece is clearly aimed at the Donald Trump government, which has always denied the ‘A’ of AGW and has pushed dangerous policies that many predict will eventually uninstall the US from the forefront of climate change negotiations as well as action. Holthaus’s piece, in this context, succeeds in painting a scary picture of the future by highlighting how much of an exception Harvey appears to be and why its occurrence isn’t one of chance.

Nonetheless, the piece did still make me wonder if the world paid as much attention to the 2015 Tamil Nadu floods as it is paying to Harvey. Sure, Holthaus is writing against the backdrop of an American president who recently said the world’s largest polluter would not abide by the terms of the Paris Agreement, and against the backdrop of a city receiving about 50 inches of rain in less than a week. In contrast, Narendra Modi has been generally accepting of the fact that climate change is real and will require drastic action (although that hasn’t stopped his government from continuing the UPA’s work to weaken institutional environmental protection safeguards or the NITI Aayog from drafting an energy policy that will ensure India remains dependent on fossil fuels until 2040).

Second: unlike Houston, the parts of Tamil Nadu that were wrecked in November-December 2015 were relatively underdeveloped areas rife with illegal constructions and pavements that effectively resulted in those areas being, to use Holthaus’s term, “flood factories”. Thus, 20 inches of rain is likelier to be deadlier in the cities of Tamil Nadu than in Houston.

But this doesn’t make it harder to distinguish between the effects of AGW-driven storms in, say, Chennai and the effects of poor urban infrastructure. Our preparedness for the effects of climate change is both mitigating global avg. surface temperature rise and better planning public spaces and improving the distribution/accessibility of resources. So if Chennai, or any other place, isn’t prepared to handle 20 inches/day of rain, it’s going to get doubly screwed in a world whose surface is (at least) 2º C hotter on average about eight decades from now.

Anyway, the north Indian mainstream media (more widely consumed by far) was mostly apathetic to the plight of Tamil Nadu’s residents during the 2015 floods – just the way the Western media at large has been relatively more apathetic towards Oriental tragedies. I think this resulted in a big opportunity missed by national-level newsrooms to cast the floods as the face of both urban and rural India’s experience with climate change, perhaps even as the face of climate change itself, and use that to underscore the state’s abject underpreparedness – for which successive state governments would have been to blame – and the Narendra Modi government’s two-faced relationship with the demands of climate change. (E.g. accepting them gleefully in some ways – e.g. by the MNRE – but blatantly ignoring them in others – e.g. by the MoEFCC – and which I’d argue is more insidious than claiming outright that climate change is codswallop.)

Establishing trust across the aisle on issues of climate change

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Featured image: An image from a shipborne NASA investigation to study how changing conditions in the Arctic affect the ocean’s chemistry and ecosystems. Credit: gsfc/Flickr, CC BY 2.0.

I met someone over the weekend who wasn’t sure:

  1. That there is scientific consensus on the magnitude of anthropogenic global warming (AGW), and
  2. What the level of human contribution is to rising temperatures (or, how much natural variations could/couldn’t account for)

I believe that AGW is valid and that, if we don’t do something about the way we’re using Earth’s natural resources, AGW will be extremely damaging to the environment as soon as a century from now (to be even more proper about it: that AGW will force nature to adapt in ways that will no longer preserve characteristics that we have been able to attribute to it for thousands of years). This said: I’m not here to describe how the conversation with my friend went but to highlight two specific sources of information that were in play last night and which I think are worth discussing because of their attempts at coming off as trustworthy.

An ivory tower from the inside

In May 2013, John Cook et al published a paper titled ‘Quantifying the consensus on anthropogenic global warming in the scientific literature’. It was a literature review of 11,944 papers published in 1,980 journals, all papers dealing with climate change. Using a large team of volunteers, the authors then classified each paper into one of five groups depending on what its abstract said about the paper’s position on climate change. These were the results:

rucyo-1

(Obviously the links within the image aren’t clickable, so if you’re looking for the data: the paper’s open access.) At the time of publication, the paper received a lot of play in the media – largely because of the numbers in the first row, columns two and four. According to it, 97.1% of all papers that have a position on AGW endorse AGW and 98.% of all authors that have a position on AGW endorse AGW. However, both the giant numbers don’t correspond to the 11,944 abstracts surveyed but the 3,893 (32.6%) that the authors qualified as having a position on AGW.

Clearly, the way to interpret John Cook et al would’ve been to say it like Der Spiegel did: ‘Von knapp 4000 Studien, die die Ursachen der Klimaerwärmung thematisierten, stützen 97 Prozent die Annahme vom menschgemachten Klimawandel’ (“Of nearly 4,000 studies dealing with the causes of climate warming, 97 percent support the assumption of human-driven climate change”). However, my friend – during the course of his arguments – often lingered on the 66.7% (7,966) of all papers that were uncertain about or refused to take a position on AGW. Specifically, he took the exclusion of these papers from the calculation that arrived at a number like “97.1%” to be misguided. After all, he reasoned, ~8,000 papers out of ~12,000 had seen it fit to not explicitly endorse AGW.

Dana Nuccitelli and John Cook, two of the paper’s authors, tried to explain these numbers thus on the Skeptical Science blog:

We found that about two-thirds of papers didn’t express a position on the subject in the abstract, which confirms that we were conservative in our initial abstract ratings. This result isn’t surprising for two reasons: 1) most journals have strict word limits for their abstracts, and 2) frankly, every scientist doing climate research knows humans are causing global warming. There’s no longer a need to state something so obvious. For example, would you expect every geological paper to note in its abstract that the Earth is a spherical body that orbits the sun?

I don’t buy it. The first sentence – “We found that about two-thirds of papers didn’t express a position on the subject in the abstract, which confirms that we were conservative in our initial abstract ratings” – is more of a self-fulfilling prophecy than anything else. The first part of the second sentence requires even more analysis to verify, considering the 11,944 papers they parsed appeared in 1,980 journals, and the fraction of journals that set a word-limit for the abstract might just be non-trivial. The second part is, to me, the display of off-putting arrogance. Doesn’t saying “frankly, every scientist doing climate research knows humans are causing global warming” imply the authors are being dismissive of their own conclusions? And finally, that Earth orbits the Sun is far more obvious than a thesis the defence of which rests on the presumption that the thesis is right – a circularity that renders all facts moot.

While none of this makes me question the validity of AGW, which I still endorse for various reasons, Nuccitelli-Cook’s pseudo-defence doesn’t help me trust them in particular. In fact, their position makes me more suspicious of why they arrived at a number like 32.6% when they were assuming at the outset that it would really be 100%.

An attempt to escape the tower

As it happens, Nuccitelli-Cook don’t appear to be in the minority. To assume that all climate researchers know AGW is valid is also to presume that those who dispute its existence or extent are not really climate researchers (if they’re in the same field) – and this appears to be the case with Judith Curry’s detractors. Until a week ago, Curry was the chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, Atlanta (she quit on January 1). She shot into the limelight in 2005 after coauthoring a paper that linked a rising incidence of hurricanes with AGW. However, it wasn’t the conclusion of the paper itself but what it led to that put Curry on the climatological map: she began to engage actively with climate skeptics on blogs and other fora in an effort to defend the methods of her paper. And this, for some reason, infuriated her colleagues. A profile of Curry in Nature in 2010 said:

Climate skeptics have seized on Curry’s statements to cast doubt on the basic science of climate change. So it is important to emphasize that nothing she encountered led her to question the science; she still has no doubt that the planet is warming, that human-generated greenhouse gases, including carbon dioxide, are in large part to blame, or that the plausible worst-case scenario could be catastrophic. She does not believe that the Climategate e-mails are evidence of fraud or that the IPCC is some kind of grand international conspiracy. What she does believe is that the mainstream climate science community has moved beyond the ivory tower into a type of fortress mentality, in which insiders can do no wrong and outsiders are forbidden entry.

But Curry’s position has diverged further since: On April 15, 2015, Curry testified before the US House of Representatives Committee on Space, Science and Technology that she didn’t think scientists knew how much humans influenced the climate, especially since the 1950s. This was discomfiting to discover because now I’m suspecting what qualms Curry had with climate science itself instead of only with the attitudes subsection of it. Ken Rice, a computational astrophysicist at the University of Edinburgh, commented at the time:

Again with all the we don’t knows. Yes, we might not know but we have a pretty good idea of what caused the Little Ice Age (reduced solar insolation and increased volcanic activity) and it was obviously not attributed to humans. Why is that even worth mentioning? Again, we might not know what will happen in the 21st century, but we have a fairly good idea of what will happen if we continue to increase our emissions.

So, if we’re going to move forward by acknowledging that what we’ve been trying so far has failed and that others should have a stronger voice, why would we do so if some of those others don’t appear to know anything? Given this, I’ll expand a little on my thoughts with regards to [Steven] Mosher’s point that with regards to policy, science doesn’t much matter. Yes, in some sense I agree with this; let’s stop arguing about science and just get on with deciding on the optimal policies. However, science does inform policy and I fail to see how we can develop sensible policy if we start with the view that we don’t know anything.

In the same vein: what reason is there to get out of the ivory tower at all if, from within, climate scientists have been able to accomplish so much? The simplest answer would be that Donald Trump is set become the 45th president of the US about eleven days from now, and the millions who voted him to power don’t care that he’s a climate skeptic. Even if outgoing president Barack Obama believes that the American adoption of clean energy is irreversible, what Trump could do is destabilise American leadership of international climate negotiations. AGW-endorsers sitting within their comfort zones of Numbers Don’t Lie could find this a particularly difficult battle to win because the IPCC and its brand of questionable integrity is doing no one any favours either. Even if the body’s on the “right” side of things, its attitude has been damaging to say the least (sort of like GMO and Monsanto).

Keith Kloor, former editor of Audubon, recently wrote on Issues of Science and Technology,

Donald Trump’s improbable march to the White House shocked many, but the tactics that made it possible undoubtedly looked familiar to those of us who have navigated the topsy-turvy landscape of contested science. For Trump’s success was predicated on techniques that are used by advocates across the ideological spectrum to dispute or at least muddy established truths in science. … With the ascension of Trump in 2016, have we graduated from truthiness to what some political observers are now calling the post-truth era? Post-truth is defined by Oxford Dictionary as a state in which “objective facts are less influential in shaping public opinion than appeals to emotion.” But this doesn’t do justice to the bending of reality by Trump en route to the White House. You can’t do that simply with appeals to emotion; you need, as his triumph suggests, a made-for-media narrative, with villains, accomplices, and heroes. You need to do what has already been proven to work in warping public perceptions and discussion of certain fields of science.

Those who believe Curry shouldn’t engage with skeptics because her decision could be interpreted as a prominent academic exiting the pro-AGW camp is difficult to buy into – even if Curry did switch camps. It’s hard to arbitrate because there are two variables: the uncertainties inherent in climate modelling (even if the bigger picture still endorses AGW) and how that proselytised someone of the calibre of Judith Curry. Surely the (former) head of a reputed department at Georgia Tech is not the same as any other skeptic?

I thought it was common sense to engage with people from across the aisle instead of letting them persist with information they think is credible but which you think is incredible – to the point that, over time, you become habituated to disregard them irrespective of the legitimacy of their demands. Moreover, giving room for people to disagree with you, to engage with them by making your methods and data available, and working with them to conduct replication studies that test the robustness of your own methods are all features of research and publishing that are being increasingly adopted to everyone’s benefit, most of all science’s.

It’s not hard from here-now to see that moving the other way – by making people anxious even to ask honest questions, by robbing them of the opportunity to respectfully disagree – isn’t going to do much good. Being nice also helps maintain a non-fragmented community that doesn’t further legitimise the impression that “science doesn’t matter when it comes to policy”.

Has ‘false balance’ become self-evidently wrong?

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Featured image credit: mistermoss/Flickr, CC BY 2.0.

Journalism’s engagement with a convergent body of knowledge is an interesting thing in two ways. From the PoV of the body, journalism is typically seen as an enabler, an instrument for furthering goals and which is adjacent at best until it begins to have an adverse effect on the dominant forces of convergence. From the PoV of journalism, the body of knowledge isn’t adjacent but more visceral – the flesh with which the narratives of journalistic expression manifest themselves. Both perspectives are borne out in the interaction between anthropogenic global warming (AGW) and its presence in the news. Especially from the PoV of journalism, covering AGW has been something of a slow burn because the assembly of its facts can’t be catalysed even as it maintains a high propensity to be derailed, requiring journalists to maintain a constant intensity over a longer span of time than would typically be accorded to other news items.

When I call AGW a convergent body of knowledge, I mean that it is trying to achieve consensus on some hypotheses – and the moment that consensus is achieved will be the point of convergence. IIRC, the latest report from the Intergovernmental Panel on Climate Change says that the ongoing spate of global warming is 95% a result of human activities – a level of certainty that we’ll take to be just past the point of convergence. Now, the coverage of AGW until this point was straightforward, that there were two sides which deserved to be represented equally. When the convergence eliminated one side, it was a technical elimination, a group of fact-seekers getting together and agreeing that what they had on their hands was indeed a fact even if they weren’t 100% certain.

What this meant for journalism was that its traditional mode of creating balance was no longer valid. The principal narrative had shifted from being a conflict between AGW-adherents and AGW-deniers (“yes/no”) to becoming a conflict between some AGW-adherents and other AGW-adherents (“less/more”). And if we’re moving in the right direction, less/more is naturally the more important conflict to talk about. But post-convergence, any story that reverted to the yes/no conflict was accused of having succumbed to a sense of false balance, and calling out instances of false balance has since become a thing. Now, to the point of my piece: have we finally entered a period wherein calling out instances of false balance has become redundant, wherein awareness of the fallacies of AGW-denial has matured enough for false-balance to have become either deliberate or the result of mindlessness?

Yes. I think so – that false-balance has finally become self-evidently wrong, and to not acknowledge this is to concede that AGW-denial might still retain some vestiges of potency.

I was prompted to write this post after I received a pitch for an article to be published on The Wire, about using the conclusions of a recently published report to ascertain that AGW-denial was flawed. In other words: new data, old conclusions. And the pitch gave me the impression that the author may have been taking the threat of AGW-deniers too seriously. Had you been the editor reading this, would you have okayed the piece?

The global warming hiatus could last another five years. Its aftermath is the real problem.

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Whether you’ve been fending off climate-change skeptics on Twitter or have been looking for reasons to become a climate-change skeptic yourself, you must’ve heard about the hiatus. It’s the name given to a relatively drastic drop in the rate at which the world’s surface temperatures have increased, starting since the late 1990s, as compared to the rate since the early 1900s. Even if different measurements have revealed different drops in the rate, there’s no doubt among those who believe in anthropogenic global-warming that it’s happening.

According to one account: between 1998 and 2012, the global surface temperature rose by 0.05 kelvin per decade as opposed to 0.12 kelvin in the decades preceding it, going back to the start of the previous century. To be sure, the Earth has not stopped getting warmer, but the rate at which it was doing so got turned down a notch for reasons that weren’t immediately understood. And even as climate-scientists have been taking their readings, debate has surged about what the hiatus portends for the future of climate-change.

Now, a new study in Nature Climate Change has taken a shot at settling just this debate. According to it: The chances that a global-warming hiatus will happen for 10 consecutive years is about 10%, but that it will happen for 20 consecutive years is less than 1%. Finally, it says, if a warming hiatus has lasted for 15 years, then the chances it will last for five more years could be as high as 25%. So that means the current letoff in warming is somewhat likely to go on till 2020.

The study was published on February 23, titled pithily, Quantifying the likelihood of a continued hiatus in global warming. It focuses on the effects of internal variability, which – according to the IPCC – is the variability due to internal processes in the climate system (such as the El Niño Southern Oscillation) and excluding external influences (such as volcanic eruptions and sulphate aerosol emissions).

At the least, the statistically deduced projections empower climate scientists by giving them a vantage point from which to address the slowdown in warming rates since the start of this century. But more significantly, the numbers and methods give observers – such as those in the government and policy-makers – a perspective with which to address a seeming anomaly that has come at a crucial time for tackling anthropogenic global warming.

Global mean land-ocean temperature index from January 1970 through January 2014. The colored line is the monthly mean and the black line is the five-year running mean. The global warming hiatus referenced in literature commonly starts circa 2000.
Image: DHeyward/CC-BY-SA 3.0

Its timing (as if it could be timed) was crucial because it coincided with the same decade in which most of the faster-growing economies on the planet were circling each other in the negotiation bullring, wanting to be perceived as being committed to protecting the environment while reluctant about backing down on growth-rate reforms. The slowdown was a not-insurmountable-yet-still-there stumbling block to effectively mobilizing public debate on the issue. Needless to say, it also made for fodder for the deniers.

Wryly enough, the Nature Climate Change study shows that it is not an anomaly that’s about to let anybody off the hook but a phenomenon actually consistent with what we know about internal climate variability, and that such an event though rare could last two full decades without defying our knowledge. In fact, throw in coincident external variability and we have the additional possibility of longer and stronger hiatus periods in reality.

Anyway, there is yet more cause for alarm with this assertion because it suggests that some natural entity – in this case the sub-surface Pacific Ocean – is absorbing heat and causing the hiatus. Once a threshold is reached, that accumulated heat will be released in a sustained burst of about five years. The study’s authors term this the period of ‘accelerated warming’, when the oceans release 0.2 W/m2 of energy in “a pattern … that approximates a mirror image of surface temperature trends during hiatus periods”.

The analysis was based on data obtained from the Coupled Carbon Cycle Climate Model Intercomparison Project (Phase 5), which assesses changes in the climate due to changes in the carbon cycle in the presence of external variables. And simulations using it helped the researchers highlight a worrying discrepancy from previous predictions for the Arctic region:

Hiatus decades associated with internal variability in models generally exhibit cooling over the Arctic whereas recent observations indicate a strong warming. Our results indicate that, following the termination of the current global warming hiatus, internal climate variability may act to intensify rates of Arctic warming leading to increased climate stress on a region that is already particularly vulnerable to climate change.

The Arctic isn’t the only region that’s in trouble. The authors also predict that the period of accelerated warming will be “associated with warming across South America, Australia, Africa and Southeast Asia”. This doesn’t bode well: developing nations have been found to be especially susceptible to the adverse effects of anthropogenic warming because of their dependence on agriculture and for being under-prepared for catastrophic weather events.

Even if climate talks are beginning to focus on goals for the post-2020 period, this predicted asymmetry of impact won’t be at the top of negotiators’ minds at the 21st annual Conference of the Parties to the UNFCCC in Paris on November 30. However, should it transpire, the slowdown-speedup tendencies of climate variability could further muddle negotiations already fraught with shifting alliances and general bullheadedness.