CLIMATE CONFESSION: I WAS WRONG

The following post was written by Dr. Jeff Kargel.

I am a glaciologist and planetary scientist, now at the Planetary Science Institute, formerly at the University of Arizona and US Geological Survey. I cofounded, then directed Global Land Ice Measurements from Space. My work involves remote sensing and field studies of glaciers, glacial lakes, and landslides. I apply science to human concerns when earthquakes hit mountains, glacial lakes burst, landslides and avalanches dam rivers, or when mountain disasters destroy oil pipelines, highways, villages and military bases.

My earliest University studies in geology taught me about natural coal ages and ice ages. I became concerned about human-caused climate change in the 1980s when the scientific community’s alarm amped up about industrial emissions of carbon dioxide and other heat-trapping gases. The basic physics is not complex. Human-caused global warming was predicted in the 1890s by Svante Arrhenius and Thomas Chrowder Chamberlin. They recognized that fluctuations in atmospheric carbon dioxide and water vapor explain the ice ages and interglacials, and that industrial emissions of carbon dioxide eventually would alter Earth’s climate.

If not for greenhouse gases, the Earth would be gripped by a permanent global ice age. But if too much of these gases are added rapidly, then climate change is injurious. Venus, where surface temperatures are near 750 degrees F, has an extreme “super-greenhouse.” Mars, on the other hand, has so little greenhouse gas that, together with its greater distance from the Sun, keeps it more frigid than Antarctica.

Imja Lake, Nepal, near Mount Everest. The lake started as ponds on the glacier surface in the early 1960s; growth has gradually accelerated as the glacier retreated. This is the archetypical hazardous glacial lake, reaching about 150 m (500 feet) deep, 2700 m (1.7 miles) long, all of which was ice until the lake replaced it (Haritashya et al. 2018). The dark blue pond— Amphulapcha Lake— also has a signature of having melted into an ice-bearing substrate. Photo by J. Kargel, 26 Oct 2015.

Global climate is normally regulated by geology and Earth’s rotational wobble, solar physics, and Jupiter’s gravitational tug on our planet’s orbit. The drift of continents and emissions of volcanic gases can cause the climate balance to be tipped toward a full ice age; or to a full hot house, where rain wears down the continents and mountains are partly replaced by global swamps— organic accumulations then eventually form coal, oil, and natural gas.  These swings happen naturally, primarily slowly, and life adapts accordingly.

Civilization has grown during a relatively stable climate. Small natural climate swings have caused famines, desertification, and spread of grasslands, affecting nomadic, agricultural, and urban societies. Natural climate changes have caused civilizations to collapse, including a 13th century mega-drought induced failure of the Anasazi and other Pre-European Native cultures in and near my state of Arizona.

In 2004— a US Presidential election year— my agency (USGS) caved in to the climate change denialism of President George W. Bush, a former oilman, who apparently didn’t want understanding of greenhouse gases and a warming planet to spread among the public. Public communications about the science of glaciers and climate change were stymied. I resigned my civil servant position so that nobody could dictate my public communications. Never one to tolerate either climate change exaggeration or climate change obfuscation, I did not participate in the minimization and hiding of evidence for climate change. I always thought that the modern global economy can adapt and mitigate 21st century impacts from a couple degrees of human-caused climate warming. (And we can if we are smart about it.)

Around 2005, I started paying attention to the continuing work by Dr. Jennifer Francis (then at Rutgers University, now Woods Hole Research Center). The melting of Arctic sea ice, predicted in 1981 by Jim Hansen and colleagues, already was underway. Francis had linked the fast-warming Arctic and melting sea ice to shifts in the behavior of Earth’s jet streams — the great rivers of stratospheric air that guide storms, speed eastward-bound airliners, and slow westward flights. The now familiar, dreaded, related winter weather phenomena known as snowmaggedons, polar vortex disruptions, and bomb cyclones also had begun, and extreme drought and heat waves in both summer and winter were being reinforced by slowly moving or stationary and wildly meandering jet streams— the kind of extreme weather that Francis with colleagues has explained, other climatologists have also supported, and which the public is grasping in terms of consequences.

I was not thinking about abruptly changing behaviors of the gigantic currents of the Earth’s atmosphere and oceans. In 2005, I thought that climate change was gradual and readily manageable. I was wrong. I didn’t consider nonlinear effects— the tipping points— that climate change would have on individual components of the Earth system.

Hurricane Katrina hit also in 2005, and since then a succession of Category 4 and 5 hurricanes have struck North America and Asia, and year-upon-year of ever-warmer, record-warm conditions have hit worldwide. The climate and extreme weather news just in 2019 and 2020 is alarming not just to scientists but to a wider public. Jennifer Francis is onto something big, as she has connected climate change to extreme weather with a climatological understanding as almost nobody else had previously done. Forest fires have raged seasonally on six continents at levels that previously were uncommon or historically unprecedented. Wildfires have become an increasingly frequent feature of the past two decades’ evening news in California, Alaska, Australia, Scandinavia, and Siberia. Wildfire links to climate change are understood scientifically and were predicted and are also understood by the public.

As if the changing atmospheric circulation isn’t enough, there is increasing evidence that some ocean currents are changing from historic behavior. In 2014 I attributed part of the variability in glacier behavior to regional adjustments of ocean currents to shifting global climate. Overall, glaciers started melting 150 years ago in response to a modest natural warming episode earlier in the 19th century, and since the 1990s the melting binge has speeded dramatically. This behavior recently extends to the Greenland ice sheet and parts of Antarctica.

A finely tuned Earth system from a century ago has become more disrupted than at any time in human civilization, by some measures more than since modern humans (Homo sapiens) have lived, and by other measures more than going back halfway to the age of dinosaurs.  Carbon dioxide levels assure that much more change is pent up and is coming our way.

My confession is that the signs and the models were in place by 2005, but I was still thinking in gradualistic terms. I was not thinking about abruptly changing behaviors of the gigantic currents of the Earth’s atmosphere and oceans. In 2005, I thought that climate change was gradual and readily manageable. I was wrong. I didn’t consider nonlinear effects— the tipping points— that climate change would have on individual components of the Earth system. My change of perspective stemmed partly from my own research into melting glaciers and the roles of exceptional heat or rain in triggering glacier surges, ice avalanches, and glacial lake outbursts, and that these processes involve climate-tipping points and glaciological tipping points. But then there were record breaking hot summers and drought in my home state of Arizona, and record breaking wildfires nearby in California. Those are just the impacts I personally deal with every year. Globally there are so many 500-year floods, 500-year droughts, unprecedented firestorms, so many $10 billion and $100 billion hurricanes that we forget their names, and bizarre weather patterns that have no place in history. At some point, we run out of excuses that it’s just an anomaly for this, and a different anomaly for that. The recognition hits: the data on greenhouse gases and global warming connect to the climate models, and the models connect to the observed rise in extreme weather, and lately, to burning koalas and kangaroos.

Imja Lake and its natural end moraine dam. The great width and bouldery constitution of the dam naturally decreases the instability of this lake compared to some others. However, the moraine is ice cored and is slowly melting, and the small ponds along the drainageway are growing and slowly reducing the effective width and protective features of the natural dam. Meanwhile, as the lake continues to expand at the glacier end of the lake (Haritashya et al. 2018), it will soon enter a region where large rock and ice avalanches can impact the lake directly and send a tsunami-like wave ramping up over the end moraine. To counter this rising hazard, a decision was undertaken to slightly lower the lake and stabilize the drainage conduit. The engineering was completed in 2016. Eliminating the hazard is not feasible. Modest further reductions in the hazard can be undertaken, but risk mitigation should focus on adaptation along the potential flood course, such as moving the most vulnerable downstream homes and hotels in some downstream villages to a little higher ground. Photo by J. Kargel, 26 Oct 2015.

Scientists are by nature cautious in our technical work. However, it can become misleading, even unethical, to leave the public with what to them is a confusing concept of statistical uncertainties and error bars and confidence limits; our language must not obscure the underlying understanding and urgency that the scientific community has about what is happening and why and what is coming.

Earth will not turn into a Venus, but my planetary science mind definitely sees how rain forests turn to deserts, how nations lose their food supplies, and wars erupt. The climate system is in upheaval, and global climate change has global economic reach of course. As a scientist, I see that the gap between climate models and extreme weather observations is not yet closed at the local and regional levels. It is locally and regionally where the most serious impacts of climate change nonlinearities— the tipping points— are being felt. In politics, as a famous American House Speaker once said, “All politics is local.” In climate, we ought to take the same approach to inform public understanding. People care about burning koalas, but they will vote on climate change when they see the local connections.

Fifteen years after my enlightenment, we have more than a crisis, arguably not yet an apocalypse. The planet has been through worse. But humanity, aside maybe from Homo robustus, has never witnessed such drastic changes to our environment, a period now known to geologists as the Anthropocene. Civilization is slowly preparing, but not on a schedule to match climate change’s impacts on people, dollars, and nature.

Scientists, economists, engineers, and business people— and many politicians— know what should be done and how to do it. We can affordably transform our economy to move off fossil fuels. Most nations want to do this. Roadblocks against international climate change agreements and national policy initiatives are erected by crafty saboteurs, who use “manufactured doubt” about climate change. They implement myriad infrastructural supports and subsidies for 20th century technologies to keep the world hooked on fossil fuels.

It might be too late. I am not of a view that is already clearly too late. Too late for what? The worst? No, it is not too late to make things worse. After a depressing January, my almost irrepressable optimism is reasserting that we can chart and follow a better course. Politicians will come onboard, pressured by public opinion and climate change activists such as Greta Thunberg. Maybe this year’s record-breaking, nature-killing, sea-to-sea-to-sea bushfires across Australia will awaken politicians there. It’s something everywhere, every year.

Though there are hopeful political glimmers in China, the U.S. and elsewhere, the corporate world may be issuing a mandate for the needed changes. Though still attracting climate activists’ skepticism, a rather believable and substantive action plan has been announced by the $7 trillion BlackRock investments— the world’s largest investment group. Climate activists’ pressure is needed to assure follow through. Around the world, no matter what the economic system, people— powerful people especially— respond to where money flows. Furthermore, the rich and powerful have children, too. Maybe the message is getting across.

Read More on GlacierHub:

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Ancient Viruses Awaken as the Tibetan Plateau Melts

Video of the Week: First Footage From Beneath Thwaites Glacier

Are glaciers behind perplexing shift in paleoclimate Ice Age patterns?

In early August, at the Goldschmidt Conference on geochemistry, a team of scientists from Columbia University presented evidence from seafloor cores that suggest that a million years ago ice sheets in the Northern Hemisphere began sticking to their bedrock. The team proposes that as the glaciers grew thicker, it led to a global cooling that disrupted both the Atlantic Meridional Overturning Circulation (AMOC) and the ice age cycle. But how exactly might glaciers have been involved in this perplexing shift in paleoclimate ice age patterns?

As skeptics of anthropogenic climate change often note, Earth’s climate changes and has changed before. Aside from humans’ unabashed consumption of greenhouse gases, a wide variety of natural factors cause shifts in this complex system. For instance, scientists have long acknowledged how tiny changes in the Earth’s orbit around the sun, collectively known as the Milankovitch Cycles, drive the coming and going of ice ages. As the Milankovitch Cycles interact, the planet’s movements displace the incoming solar radiation across the globe, dramatically affecting the Earth’s climate system and the advancement and retreat of glaciers.

Glaciers in the North Atlantic, such as this one in the Johan Petersen Fjord of eastern Greenland, may have driven a global cooling a million years ago (Source: Ray Swi-hymn/Flickr).

For a while, ice ages were known to occur steadily every 40,000 years. However, a million years ago, that metronome inexplicably got off course. Instead of periods of intense glaciation occurring every 40,000 years, it shifted to every 100,000 years. But the likely culprit, the Milankovitch Cycles, hadn’t changed a million years ago. It didn’t add up.

And that’s not all. Around the same time, the massive AMOC— the conveyor belt that brings warm, shallow water to the North Atlantic, where it cools and sinks to the sea floor before returning south— nearly collapsed. Were these events related? If so, how and what was behind them?

These questions have perplexed scientists for years, as was apparent even at last month’s conference. But through an analysis of the chemical composition of basin-wide ocean sediment cores over several years, geochemist Steve Goldstein from Columbia University, who led the study presented at Goldschmidt, found unique shifts in isotopic signals that reflect a slower turn of the AMOC 950,000 years ago. 

For the present study, the team examined five more ocean cores, in addition to two analyzed earlier in the decade, that also demonstrated signs of a weak AMOC. The group believes two of the cores from the North Atlantic indicate possible triggers for the AMOC crisis. They suggest that such a slowdown could have rapidly cooled the North Atlantic region, in turn lengthening the ice age rhythm.

Peter Clark, a glaciologist at Oregon State University in Corvallis, has advanced this hypothesis as the only plausible explanation for many years, wrote Paul Voosen in Science last month. Three million years ago, a sustained warming period allowed for the build-up of thick soil in the Northern Hemisphere. Ice sheets would often collapse as the soil acted as an oiled buffer. But repeated glaciations wore down the warm protective layer and enabled glaciers to dig deeper into older rock that stabilized them and helped them thicken and advance.

Aerial shot of a large glacier in Greenland (Source: Leon Weber/Flickr).

But as exciting as the findings may be, not everyone is sold on the hypothesis. Climate scientist Amy Clement from the University of Miami told GlacierHub it sounded like an interesting concept, but she has problems with how the AMOC idea is applied in the modern climate. Clement explains how some argue that variations in the AMOC strength control the North Atlantic surface temperature on these multi-decadal timescales.

“The problems are (1) timescale and (2) magnitude. On these short timescales, the AMOC doesn’t seem to be the driver,” she noted to GlacierHub. “Instead we think the North Atlantic surface temperatures are controlled by external forcing (some natural, such as the sun and volcanoes) and some anthropogenic (such as greenhouse gases and aerosols).”

Others including Henrieka Detlef, a paleoclimatologist at Cardiff University in the U.K., told Science that while she accepts something important happened in the North Atlantic to lead to AMOC crisis, she has yet to see conclusive evidence that northern ice sheets were increasing in thickness prior to the AMOC slowdown.

Still, most agree that ice age rhythm shifts were likely caused by more than one trigger. The Columbia team is confident that thickening ice sheets in addition to other factors played a role in the perplexing transition. “The interactions between the different components of the Earth’s climate are elusive, but understanding them is crucial for reconstructing past changes,” Maayan Yehudai, part of the research group and a graduate student at Columbia, told GlacierHub. “We still have a long way to go as scientists before we can characterize them perfectly, but I think this is another important step forward on this account.”