Home Glaciers Conclusion of COP26: Notes on ice and cities

Conclusion of COP26: Notes on ice and cities

0


Ice

In a personal capacity, and in connection with my past project work in Greenland and other arctic and high mountain regions, I have attended several COP26 events focused on ice science. Many took place at the Cryosphere Pavilion, one of dozens of information pavilions hosted by countries and organizations at COP26. I relate here some highlights of these events with a brief mention of the cities at the end.

The cryosphere is a term for all of the world’s snow and ice, which can be found all over the world, but which is particularly abundant at the world’s poles and in its high mountains.

Until recently, polar ice caps and major glaciers around the world were considered stable – they would grow and change on geological time scales of thousands of years. During an event at The New York Times Climate Hub, glaciologist Alun Hubbard noted that the Greenland ice sheet was in equilibrium only 20 years ago, but with current rates of change, the metaphor of an “ice rhythm” no longer makes sense. .

I attended two lectures 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 “Antarctica and Greenland are both extremely vulnerable, and we are pushing the boundaries now. And, contrary to a common narrative, Brigham-Grette sought to “challenge the idea that Antarctica is not responding to change”.

Dr. Julie Brigham-Grette of the University of Massachusetts-Amherst describes the geology underlying Greenland at the COP 26 Cryosphere Pavilion. Image by Chris Dunn. Scotland, 2021.

She offered two main examples refuting this notion.

The first is the many sea ice collapses that have already occurred in the Antarctic Peninsula, about seven out of ten. Much larger ice shelves are believed to hold back massive ice caps in other parts of Antarctica, most notably the West Antarctic Ice Sheet.

The second is the example of the Pine Island and Thwaiter Glaciers, which succumb to a combination of melting from below caused by relatively warm ocean waters and hydrofracking from above – the latter leading to an “eviscerated ice sheet of [the] inside. ”It is true that while some parts of Antarctica are warming, others are not. But the parts that are warming are large and important.

The belief that Antarctica is unaffected by warming comes from two problematic sources: first, scientists are, said Dr Brigham-Grette, “to be careful with attribution” – to make conservative projections, in other words. terms, due to a lack of past data; second, the IPCC cryosphere reports speak of ‘low probability’, but this does not mean that a given event, such as the collapse of the West Antarctic ice sheet, is unlikely (contrary to popular practice). current and therefore misinterpretations of reports), but rather refers to limited data. A member of the audience at one of the events I attended noted that India has often used this incorrect sense of low probability in the COP negotiations in the past to justify certain political positions.

Dr Brigham-Grette, along with arctic climatologist Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colorado, also gave summaries from Greenland. Greenland has, in some important places, been a very small example of what could happen on a much larger scale in Antarctica once the ice shelves are lost, with rapid acceleration of ice flow and calving occurring. . This acceleration of flow over time is also due to a feedback effect of glacial thinning and flow, and is stimulated by basal lubrication (due to meltwater flowing under glaciers). The loss of the ice sheet is expected to accelerate further once the sea ice clears around 2040-2050.

Evidence suggests that Greenland has likely lost its entire ice cap several times in the past. The greatest certainty concerns a loss that occurred 400,000 years ago. Under high emission scenarios, Greenland could be ice free by the year 3000. This is an extremely rapid rate of loss compared to the geological past.

Dr Brigham-Grette noted that “what Greenland is doing now is reacting to the climate ten years ago”. The behavior of the Greenland ice sheet, as well as other large masses of land ice, lags behind the climate. So even if we maintain a 1 degree warming (where we are approximately now), it will still cause sea level to rise six to nine meters within 500 to 1,000 years. “We have already incorporated, so to speak,” these changes, continued Dr Brigham-Grette. Most of the mass loss is currently due to surface melting rather than calving and is expected to become more dominant in the future as glaciers recede on land.

Much attention is paid to small islands and low-lying countries as well as to arctic peoples dependent on sea ice, who are experiencing some of the earliest and most dramatic impacts of climate change. Less well known are the effects on the high mountain communities of the world that live near 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.

Cryosphere pavilion
Visitors to the COP 26 cryosphere pavilion listen to a lecture. Image by Chris Dunn. Scotland, 2021.

A few things to remember are that beyond 1.5 degrees of warming, people in areas like the Andes and Himalayas are unlikely to be able to continue living there due to the loss of glaciers. Mountain people depend on glaciers for their water and are increasingly exposed to catastrophic landslides and flooding caused by melting glaciers and permafrost. Floods in glacial lakes often occur due to a combination of increased meltwater in newly formed meltwater ponds and landslides triggered by thawing of the underlying permafrost. Such floods are becoming more frequent and in some cases are expected to cross international borders, as has happened in at least one case between Nepal and China.

In places like the Indian Himalayas, dams are being built closer and closer to glaciers, which increases the risk of dam failure caused by collapsing glaciers or mountain landslides, as happened in the Indian state of Uttarkhand in february of this year.

Ice loss is significant, but even a change in the timing of the melt has an impact. In some areas like the Hindu-Kush region of the Himalayas, the “peak water” – the highest level of production from melting glaciers – has already passed and so water supplies are now on. a continuously decreasing downward trajectory.

Mountain peoples have innovated to adapt, such as ‘ice stupas’ in which water is deliberately sprayed during the colder months into a large mound of ice that will melt during the warmer months, especially after the end of the spring snowmelt. Even these clever innovations are insufficient if the warming continues. The only real long-term solution for high mountain communities is to reduce emissions.

Of course, the impacts of melting mountain glaciers are not limited to people residing at high altitudes. Billions of people around the world depend on rivers fed by meltwater from glaciers, especially in Asia.

Cities

I also had the opportunity to attend two conferences on urban centers, one with the Chilean professor Juan Carlos Muñoz and the other with the mayor of Pittsburgh, William Peduto.

Pittsburgh Mayor William Peduto
Pittsburgh Mayor William Peduto shares his efforts to tackle climate change in the city. Image by Chris Dunn. Scotland, 2021.

Cities are responsible for two-thirds of emissions, but occupy only three percent of the earth’s land area. They are not only responsible for a disproportionate amount of emissions, but are also vulnerable to climate change. Rethinking cities is therefore vital in the fight against climate change.

Dr Mu̱oz focused on transport in an urban context. He stressed the need to focus on organizing the city rather than limiting itself to transport to solve problems such as emissions and congestion. Simply replacing gasoline vehicles with electric vehicles, for example, will only result in a city that is still congested. Some of the advice he offered was to design a healthy and fair city, where shorter journeys are needed Рa 15-minute city; invest first in public transport; and not to repair the city we see, but to create the city we want.

Mayor Peduto told a story of growing up in Pittsburgh and seeing it “die” in the 1980s when there was more emigration of people than New Orleans after Hurricane Katrina due to the disappearance of industrial and manufacturing jobs. A similar loss of 100,000 fossil fuel-related jobs – including only 40,000 in West Virginia – is expected in the four-state area of ​​Pennsylvania, Kentucky, Ohio and West Virginia by 2030 .

Dr Juan Carlos Muñoz on stage
Dr Juan Carlos Muñoz from the Pontificia Universidad Católica de Chile describes the best approaches to reforming transport in cities. Image by Chris Dunn. Scotland, 2021.

Peduto contributed to the development of the Marshall Plan for Central America, an economic analysis of the transition from fossil fuels to renewable energies in one of the regions of the world most dependent on fossil fuels. It was developed in conjunction with other cities in the Midwest, with input from workers and environmentalists. The Marshall Plan for Central America is expected to create 400,000 renewable energy jobs for the region by 2030 if implemented.

Peduto also described an innovative approach he developed for the problem of methane leaks in aging pipelines in Pittsburgh. It enlisted Carnegie-Mellon University, Google and a local natural gas company to audit the pipelines at no cost to the city, using Google mapping vehicles equipped with methane sensors to locate leaks and by transmitting this data to the gas company.