If A Tree Falls in the Forest, But No Scientist Says So ...
Recently, the highly respected Bulletin of the American Meteorology Society ("BAMS" to those in the know), published a special issue consisting of a couple dozen articles investigating the potential impact climate change might have had on various extreme weather events of 2013. This has become somewhat of an annual rite now (see for example the corresponding 2012 special issue), a sort of scientific postmortem on what role climate change might have played in specific weather events.
Photo credit: Shutterstock
It might be tempting to view this volume as an authoritative statement by the scientific community on the role climate change may or may not have had in some high profile, devastating recent extreme weather events. But that would be misguided. The BAMS special issue is not a representative, community-wide scientific assessment like those published by the National Academy of Sciences or Intergovernmental Panel on Climate Change. The editors, instead, have solicited contributions from a relatively small number of groups, so the findings do not necessarily reflect the range of views of the broader scientific community. Some leading climate scientists who were not included in the effort have presented evidence of a greater role for climate change in several of the events dismissed or downplayed by the BAMS articles (see e.g. Kevin Trenberth of NCAR on the September 2013 Colorado floods, Stefan Rahmstorf of the University of Potsdam on the June 2013 Central European floods and Jennifer Francis of Rutgers on the 2013/2014 California Drought).
The California drought is of particular interest since it is both an unprecedented and absolutely devastating ongoing event. The thread potentially connecting that event to climate change is the unusual atmospheric pattern that prevailed during winter 2013/2014. That pattern was associated with a persistent "ridge" of high pressure over the western U.S. (see my previous Huffington Post piece) that caused the jet stream to plunge southward over the central U.S., chilling the eastern third of the country, and to veer northward over the west coast, pushing the warm moist subtropical Pacific air masses that would normally deliver plentiful rainfall (and snowpack) to California well to the north, resulting in bone-dry conditions in California and balmy weather in Alaska.
In fact, there are at least three different mechanisms that are potentially relevant to the connection between the 2013/2014 California drought and human-caused climate change. There is (1) the impact of climate change on the pattern of sea surface temperature (SST) off the west coast. One recent study suggests that climate change favors an SST pattern in the North Pacific that increases the incidence of the atmospheric circulation pattern responsible for the current drought. Then there is (2) the marked decrease in Arctic Sea Ice due to global warming. Studies going back more than a decade show that reduced Arctic sea ice may also favor such an atmospheric circulation pattern. More recent work by Jennifer Francis of Rutgers provides independent support for that mechanism. Finally, there is (3) the effect of global warming on soil moisture. All other things being equal, warming of soils leads to greater rates of evaporation and drying. This mechanism leads to worsened drought even if rainfall patterns are unchanged.
One of the three BAMS articles investigating the climate change connection with the California Drought (by Noah Diffenbaugh of Stanford and collaborators) did find a climate change role. They found that the high pressure ridge responsible for deflecting storms to the north was indeed made more likely by climate change. Even without accounting for increased evaporation due to warmer soils, they conclude that climate change likely increased the probability of the 2013/2014 California drought.
Two of the three BAMS articles, however, argue against a climate change connection. But here's the problem: the experimental design used in these studies completely leaves out all three of the mechanisms described above. These studies only looked at the impact of the overall warming of SSTs, without addressing whether climate change might be favoring the specific pattern of SST tied to the high pressure ridge and consequent drought. Neither of the studies accounts for the possible impact of decreasing Arctic Sea Ice (Indeed, one of the two studies explicitly acknowledges this shortcoming: "Other factors, such as the impact of climate change on the ... SST gradient and storm tracks...and changes in sea ice extent...are not examined"). Finally, neither of the studies account for the impact of warming on soil evaporation. So, the fact that two of the three studies find no climate change connection may simply point to deficiencies in the approaches used. The adage "absence of evidence is not evidence of absence" would appear to apply in spades here.
Predictably, the conflicting findings and mixed message of the BAMS report led to confused and misleading headlines like the LA Times "California drought and climate warming: Studies find no clear link". Contrast that with Stanford's press release "Causes of California drought linked to climate change, Stanford scientists say" and the Sacramento Bee commentary "Droughts likely to be new normal for California."
I fear that the problem here runs far deeper than the specific flaws in the experimental designs of certain studies. What is most problematic is an over-dependence on climate model "detection and attribution" approaches for assessing the impact of climate change on the likelihood of extreme weather events. That machinery fails when the approaches used in these studies fail to capture real-world processes that may be critical to these relationships. The failure to identify a climate change impact may simply represent a failure on the part of the chosen model to capture real world processes, rather than the absence of a climate change influence on the events in question.
I'm troubled that this latter possibility receives such short thrift in many of the articles in the BAMS volume. Indeed, a quote by UK scientist Myles Allen in the New York Times' coverage of the BAMS findings encapsulates the hubris by some climate researchers: "If we don't have evidence, I don't think we should hint darkly all the time that human influence must be to blame somehow." Never mind the caricature of his fellow scientists here as furtively attempting, in the absence of any evidence, to blame every weather event on climate change (who are these scientists that Allen speaks of? I've never read any quotes by climate scientists that could possibly be characterized this way). The real problem is the lack of humility among some scientists when it comes to evaluating the potential impacts that climate change may be having on our environment. As leading climate scientist Kevin Trenberth has put it, "The environment in which all storms form has changed owing to human activities." Trenberth notes that global warming has already increased the average amount of water vapor in the atmosphere by about 4 percent, "extra moisture flowing into the storms that produced the heavy rains and likely contributed to the strength of the storms through added energy."
In other words, climate change has fundamentally altered the atmospheric environment in which all weather takes place, and has very likely increased the frequency and intensity of various types of extreme weather, including more intense flooding events, more extensive continental drought, more extreme heat and more intense storms. Just because an event hasn't been positively "attributed" to climate change in a formal "detection & attribution" study does not preclude speaking about the role climate change may have played, when the event is (a) consistent with expectations in a warming world, and (b) part of a larger trend. A negative finding in an attribution study could be a consequence of deficiencies in the experimental design. And the notion that scientists could possibly publish a peer-reviewed article for every weather event that may have been influenced by climate change is, on its face, absurd.
And so to return to where we started, just as a tree that falls in the forest did so whether or not a scientist was there to observe it, an extreme weather event influenced by climate change was thusly influenced, whether or not a scientist published a peer-reviewed article establishing so. We should keep that in mind when we talk about the ways that climate change is already impacting extreme weather, and likely to impact it further if we do nothing to reduce the ongoing warming of the planet.
Michael Mann is Distinguished Professor of Meteorology at Pennsylvania State University and author of The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (now available in paperback with a new guest foreword by Bill Nye "The Science Guy")
YOU MIGHT ALSO LIKE
- New Clues Help Monarch Butterfly Conservation Efforts - EcoWatch ›
- Monarch Butterflies Will Be Protected Under Historic Deal - EcoWatch ›
EcoWatch Daily Newsletter
California faces another "critically dry year" according to state officials, and a destructive wildfire season looms on its horizon. But in a state that welcomes innovation, water efficacy approaches and drought management could replenish California, increasingly threatened by the climate's new extremes.
- Remarkable Drop in Colorado River Water Use Sign of Climate ... ›
- California Faces a Future of Extreme Weather - EcoWatch ›
Wisdom the mōlī, or Laysan albatross, is the oldest wild bird known to science at the age of at least 70. She is also, as of February 1, a new mother.
<div id="dadb2" class="rm-shortcode" data-rm-shortcode-id="aa2ad8cb566c9b4b6d2df2693669f6f9"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1357796504740761602" data-partner="rebelmouse"><div style="margin:1em 0">🚨Cute baby alert! Wisdom's chick has hatched!!! 🐣😍 Wisdom, a mōlī (Laysan albatross) and world’s oldest known, ban… https://t.co/Nco050ztBA</div> — USFWS Pacific Region (@USFWS Pacific Region)<a href="https://twitter.com/USFWSPacific/statuses/1357796504740761602">1612558888.0</a></blockquote></div>
By Hui Hu
Winter is supposed to be the best season for wind power – the winds are stronger, and since air density increases as the temperature drops, more force is pushing on the blades. But winter also comes with a problem: freezing weather.
Comparing rime ice and glaze ice shows how each changes the texture of the blade. Gao, Liu and Hu, 2021, CC BY-ND
Ice buildup changes air flow around the turbine blade, which can slow it down. The top photos show ice forming after 10 minutes at different temperatures in the Wind Research Tunnel. The lower measurements show airflow separation as ice accumulates. Icing Research Tunnel of Iowa State University, CC BY-ND
While traditional investment in the ocean technology sector has been tentative, growth in Israeli maritime innovations has been exponential in the last few years, and environmental concern has come to the forefront.
theDOCK aims to innovate the Israeli maritime sector. Pexels<p>The UN hopes that new investments in ocean science and technology will help turn the tide for the oceans. As such, this year kicked off the <a href="https://www.oceandecade.org/" target="_blank" rel="noopener noreferrer">United Nations Decade of Ocean Science for Sustainable Development (2021-2030)</a> to galvanize massive support for the blue economy.</p><p>According to the World Bank, the blue economy is the "sustainable use of ocean resources for economic growth, improved livelihoods, and jobs while preserving the health of ocean ecosystem," <a href="https://www.sciencedirect.com/science/article/pii/S0160412019338255#b0245" target="_blank" rel="noopener noreferrer">Science Direct</a> reported. It represents this new sector for investments and innovations that work in tandem with the oceans rather than in exploitation of them.</p><p>As recently as Aug. 2020, <a href="https://www.reutersevents.com/sustainability/esg-investors-slow-make-waves-25tn-ocean-economy" target="_blank" rel="noopener noreferrer">Reuters</a> noted that ESG Investors, those looking to invest in opportunities that have a positive impact in environmental, social and governance (ESG) issues, have been interested in "blue finance" but slow to invest.</p><p>"It is a hugely under-invested economic opportunity that is crucial to the way we have to address living on one planet," Simon Dent, director of blue investments at Mirova Natural Capital, told Reuters.</p><p>Even with slow investment, the blue economy is still expected to expand at twice the rate of the mainstream economy by 2030, Reuters reported. It already contributes $2.5tn a year in economic output, the report noted.</p><p>Current, upward <a href="https://www.ecowatch.com/-innovation-blue-economy-2646147405.html" target="_self">shifts in blue economy investments are being driven by innovation</a>, a trend the UN hopes will continue globally for the benefit of all oceans and people.</p><p>In Israel, this push has successfully translated into investment in and innovation of global ports, shipping, logistics and offshore sectors. The "Startup Nation," as Israel is often called, has seen its maritime tech ecosystem grow "significantly" in recent years and expects that growth to "accelerate dramatically," <a href="https://itrade.gov.il/belgium-english/how-israel-is-becoming-a-port-of-call-for-maritime-innovation/" target="_blank" rel="noopener noreferrer">iTrade</a> reported.</p><p>Driving this wave of momentum has been rising Israeli venture capital hub <a href="https://www.thedockinnovation.com/" target="_blank" rel="noopener noreferrer">theDOCK</a>. Founded by Israeli Navy veterans in 2017, theDOCK works with early-stage companies in the maritime space to bring their solutions to market. The hub's pioneering efforts ignited Israel's maritime technology sector, and now, with their new fund, theDOCK is motivating these high-tech solutions to also address ESG criteria.</p><p>"While ESG has always been on theDOCK's agenda, this theme has become even more of a priority," Nir Gartzman, theDOCK's managing partner, told EcoWatch. "80 percent of the startups in our portfolio (for theDOCK's Navigator II fund) will have a primary or secondary contribution to environmental, social and governance (ESG) criteria."</p><p>In a company presentation, theDOCK called contribution to the ESG agenda a "hot discussion topic" for traditional players in the space and their boards, many of whom are looking to adopt new technologies with a positive impact on the planet. The focus is on reducing carbon emissions and protecting the environment, the presentation outlines. As such, theDOCK also explicitly screens candidate investments by ESG criteria as well.</p><p>Within the maritime space, environmental innovations could include measures like increased fuel and energy efficiency, better monitoring of potential pollution sources, improved waste and air emissions management and processing of marine debris/trash into reusable materials, theDOCK's presentation noted.</p>
theDOCK team includes (left to right) Michal Hendel-Sufa, Head of Alliances, Noa Schuman, CMO, Nir Gartzman, Co-Founder & Managing Partner, and Hannan Carmeli, Co-Founder & Managing Partner. Dudu Koren<p>theDOCK's own portfolio includes companies like Orca AI, which uses an intelligent collision avoidance system to reduce the probability of oil or fuel spills, AiDock, which eliminates the use of paper by automating the customs clearance process, and DockTech, which uses depth "crowdsourcing" data to map riverbeds in real-time and optimize cargo loading, thereby reducing trips and fuel usage while also avoiding groundings.</p><p>"Oceans are a big opportunity primarily because they are just that – big!" theDOCK's Chief Marketing Officer Noa Schuman summarized. "As such, the magnitude of their criticality to the global ecosystem, the magnitude of pollution risk and the steps needed to overcome those challenges – are all huge."</p><p>There is hope that this wave of interest and investment in environmentally-positive maritime technologies will accelerate the blue economy and ESG investing even further, in Israel and beyond.</p>
- 14 Countries Commit to Ocean Sustainability Initiative - EcoWatch ›
- These 11 Innovations Are Protecting Ocean Life - EcoWatch ›
- How Innovation Is Driving the Blue Economy - EcoWatch ›