As a personal interest, and in relation to my past project work in Greenland and other Arctic and high-mountain locations, I attended several COP26 events focused on the science of ice. Many took place at the Cryosphere Pavilion—one of dozens of informative pavilions hosted by countries and organizations at COP26. I recount here some highlights from these events with a brief mention of cities at the end.
The cryosphere is a term for the totality of the world’s snow and ice, which can be found throughout the globe, but is particularly ample at the world’s poles and in its high mountains.
Until recently, polar ice sheets and major glaciers throughout the world were considered stable—they would develop and change on geological time scales of thousands of years. At an event at The New York Times Climate Hub, glaciologist Alun Hubbard noted that the Greenland ice sheet was in balance only 20 years ago, but that with current rates of change the metaphor of a “glacial pace” no longer make sense.
I attended two talks at the Cryosphere Pavilion where synopses on the present and future possibilities of Greenland and Antarctica were presented.
In one, glacial geologist Julie Brigham-Grette explained that “both Antarctica and Greenland are extremely vulnerable, and we’re pushing the limits on that now.” And, contrary to a common account, Brigham-Grette sought “to challenge the idea that Antarctica is not responding to change.”
She offered two primary examples refuting this notion.
The first is the many ice shelf collapses that have already occurred in the Antarctic Peninsula, around seven out of ten. Far larger ice shelves are thought to be holding back massive ice sheets in other parts of Antarctica, most notably the West Antarctic Ice Sheet.
The second is the instance of the Pine Island and Thwaiter Glaciers, which are succumbing to a combination of melting from below caused by relatively warm ocean waters and hydrofracking from the top—the latter leading to an “ice sheet gutted from [the] inside.” It is true though that while some parts of Antarctica are warming, others are not. But the parts that are warming are large and significant.
The belief that Antarctica is not affected by warming comes from two problematic sources: first, scientists are, Dr. Brigham-Grette stated, “being conservative with attribution”—making conservative projections, in other words, due to a lack of past data; second, the IPCC cryosphere reports speak of “low probability,” but this does not mean that a given occurrence, such as the collapse of the West Antarctic Ice Sheet, is unlikely (contrary to common usage and thus misinterpretations of the reports), but refers rather to limited data. An audience member at one of the events I attended noted that India has in the past often appealed to this incorrect sense of low probability in COP negotiations to justify certain policy stances.
Dr. Brigham-Grette, along with Arctic climatologist Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colorado, also gave synopses of Greenland. Greenland has in some significant places been a very small example of what could happen on a much larger scale in Antarctica once ice shelves are lost, with rapid acceleration of glacial flow and calving occurring. This acceleration of flow over time is also due to a feedback effect of glacial thinning and flow, and it is spurred on by basal lubrication (due to meltwater running beneath the glaciers). Ice sheet loss is expected to further accelerate once sea ice is lost by around 2040-50.
Evidence suggests that Greenland has likely lost the entirety of its ice sheet many times in the past. The most certainty is for a loss that occurred 400,000 years ago. Under high emissions scenarios, Greenland could be ice-free by the year 3000. This is an extremely rapid rate of loss relative to the geological past.
Dr. Brigham-Grette noted that “what Greenland is doing now is responding to climate a decade ago.” The behavior of Greenland’s ice sheet, along with other large bodies of terrestrial ice, lags the climate. Thus, even if we hold at 1 degrees of warming (where we are approximately now), this will still result in six to nine meters of sea level rise by within 500-1000 years. “We’ve already baked in, so to speak” these changes, Dr. Brigham-Grette continued. Most of the mass loss is presently due to surface melt rather than calving and is expected to become more dominant in the future as glaciers recede onto land.
A lot of attention is given to small island and low-lying nations as well as sea-ice dependent Arctic peoples as experiencing some of the earliest and most dramatic impacts of climate change. Less well-known are the effects on communities in the world’s high mountains who live in the vicinity of alpine glaciers. At a collaborative event between the Cryosphere Pavilion and the University of Geneva, experts discussed whether and how mountain communities can adapt to climate change.
A few takeaways are that beyond 1.5 degrees of warming, it is unlikely that people in regions like the Andes and the Himalayas will be able to continue living there due to glacier loss. Mountain peoples are reliant on glaciers for water and are increasingly at risk of catastrophic landslides and floods caused by melting glaciers and permafrost. Glacial lake outburst floods often occur due to a combination of increased meltwater in newly formed melt ponds and landslides triggered by the thawing of underlying permafrost. Such floods are increasingly common and are expected to in some instances cross international borders as has happened in at least one instance between Nepal and China.
In places like the Indian Himalayas, dams are built increasingly closer to glaciers, which increases the risk of dam bursts brought on by glacier collapse or mountain landslides, such as what occurred in the Indian state of Uttarkhand in February of this year.
Glacial loss is significant, but even a shift in the timing of melt is impactful. In certain area like the Hindu-Kush region of the Himalayas, “peak water”—the highest level of output from melting of glaciers—has already passed and thus water supplies are now on a continuously decreasing downward trajectory.
Mountain peoples have innovated some ways to adapt, such as “ice stupas” in which water is deliberately sprayed during colder months into a large mound of ice that will melt throughout the warmer months, particularly after snowmelt has ceased in the spring. Even these clever innovations are insufficient if warming continues. The only real long-term solution for high mountain communities is decreased emissions.
Of course, the impacts of melting mountain glaciers are not limited to people residing at high elevations. Billions of people around the world are dependent on rivers that are fed by glacial meltwater, especially in Asia.
I also had the opportunity to attend two talks on urban centers, one with Chilean professor Juan Carlos Muñoz and another with Pittsburgh Mayor William Peduto.
Cities are responsible for two-thirds of emissions, yet occupy only three percent of the Earth’s land area. They are not only culpable for a disproportionate amount of emissions but are vulnerable to climate change. Rethinking cities is thus vital in addressing climate change.
Dr. Muñoz focused on transportation in an urban context. He highlighted the need to focus on city organization rather than narrowly on transport to address issues like emissions and congestion. Simply replacing gas vehicles with electric vehicles, for instance, will only result in a city that is still congested. Some advice he offered was to design a city that is healthy and fair, where shorter trips are needed—a 15-minute city; to invest in public transportation first; and to not fix the city we see, but to create the city we want.
Mayor Peduto recounted a story of growing up in Pittsburgh and watching it “die” in the 1980s when there was more outmigration of people than New Orleans experienced after Hurricane Katrina due to the demise of industrial and manufacturing jobs. A similar loss of 100,000 fossil fuel-related jobs—with 40,000 alone in West Virginia—is expected in the four-state region of Pennsylvania, Kentucky, Ohio, and West Virginia by 2030.
Peduto helped develop the Marshall Plan for Middle America, an economic analysis of the transition from fossil fuels to renewables in one of the most fossil fuel dependent regions in the world. It was developed in collaboration with other midwestern cities, with the input of labor and environmentalists. The Marshall Plan for Middle America is anticipated to create 400,000 jobs for the region in renewable energy by 2030 if implemented.
Peduto also described an innovative approach he developed for the problem of methane leaks in aging pipes in Pittsburgh. He enlisted Carnegie-Mellon University, Google, and a local natural gas company to audit the pipes at no cost to the city, utilizing Google’s mapping vehicles outfitted with methane sensors to pinpoint leaks and passing this data on to the gas company.