Climate Change: Melting Ice and Statistical Models

Abstract

The foundation upon which the rest of this book rests is that evidence of climate change is robust and most visible in the retreating ice in glaciers. The exact speed at which the climate is changing is open to debate, it could be faster or slower, depending on models. The extent of harm also has some uncertainty, however, we agree that we need to move quickly away from fossil fuels. This has led to consideration of expanded roles for nuclear and renewables, which is the focus of the rest of this book.

Doug Brugge is the primary author of this chapter.

It is not the purpose of this book to litigate the issues around climate change itself. Rather, we accept that climate change is happening and that it is caused primarily by human activity, even if the rate and severity might be open to debate. Nevertheless, a brief review of the state of climate change and the science behind it is appropriate before we delve into the thorny issues surrounding the possible role of nuclear power in averting the worst outcomes.

As we write, there remains a robust and often frustrating public debate about the reality and nature of climate change and whether it is driven by the processes of modern industrial society. The discussion, if you can call it that, is lopsided because the evidence weighs so heavily toward confirming anthropogenic climate forcing. Public discourse still manages to be, at times, quite acrimonious.

This controversy is reminiscent of other environmental issues that rest largely on scientific evidence. The push back against science that establishes the harm of products from industry was pioneered long ago by the tobacco companies. They honed their approach first to resist evidence of harm from smoking, then to suppress or delay concerns about secondhand smoke, by focusing on the evidence being less than perfect (Brugge, 2018).

Today, it is the fossil fuel companies that have an incentive to generate what David Michaels called “The Triumph of Doubt” about the science of climate change (Michaels, 2020). Because of this, public understanding of climate change is fraught on multiple levels. A motivation for writing this book is to seek to convey science and evidence clearly, at a level that is accessible and without distortion, acknowledges the limitations of the evidence, but sets a reasonable bar (rather than impossible) for making decisions.

Significant problems with public controversies that revolve around scientific questions is that the science can be difficult for untrained people to grasp, it can be manipulated by political actors and then dramatized by the media to grab attention. A sober, thoughtful, and serious conversation can be challenging to engage amid the swirling maelstrom of angry posts on social media and poorly translated or understood science news.

The issues related to climate change can be broken down into three parts. First, is the climate warming? Second, if it is, is the warming caused primarily by human activities and, in particular, the burning of fossil fuels? Third, provided it is we humans who are the underlying cause, how rapid is the change and, based on that, how much time do we have to adjust to avoid serious consequences?

We cannot delve deeply enough here to have a nuanced discussion of the science of climate change. Rather, we seek to stake our position prior to exploring in much more detail the possible role of nuclear power for slowing climate change. If the reader is, at this point, in need of convincing that climate change is real, anthropogenic and poses consequences within decades, we suggest they seek out that literature and digest it prior to reading this book (PCC SAR SYR, 1995; Trenberth & Cheng, 2022).

We consider first the melting ice. While ice melt is not as scientifically rigorous as modeling, it has a couple of advantages. First, it is highly visible which makes it more compelling than numbers on a page or even a very clear graph. Second, while there are complexities to the processes by which climate change melts ice, the melting itself is a legitimate measure of integrated changes in temperature of air and water. Also melting ice is a more stable indicator than the weather which varies so much day to day and season to season. (Sengupta, 2023).

A key figure in documenting the melting ice is the underappreciated work of Bruce Molnia. After 42 years of service to the US Geological Survey, Dr. Molnia retired in 2019 from his position as Senior Science Advisor for National Civil Applications in the National Civil Applications Center. The core of his research career was studying the glaciers of Alaska. The title of his 2007 solo authored paper, “Late nineteenth to early twenty-first century behavior of Alaskan glaciers as indicators of changing regional climate”, explains why his research focus helped give climate change physical manifestations.

Changes, specifically “retreat”, what we might commonly think of as melting, of glaciers was one of the earliest tangible signs of climate change. In 1999 US Secretary of the Interior Bruce Babbit asked Molnia to find “unequivocal” evidence of climate change. Molnia’s paired photographs of glaciers in the past and present were his answer (Fig. 1.1; Molnia, 2007).

Fig. 1.1

Two pairs of photographs showing how the glaciers changed over time. (a) Toboggan Glacier, June 29, 1909; and (b) on September 4, 2000. Both were taken from the same location in Harriman Fiord, Prince William Sound. (c) White Thunder Ridge, Muir Inlet, Glacier Bay National Park and Preserve, August 13, 1941, by William O. Field, and (d) August 31, 2004, by Sidney Paige. There is no vegetation in the 1941 photograph. The photographs document the significant retreat of the glaciers over many decades. (Reproduced with permission from Molnia, 2007)

The science underlying glacier melting is not simple because there are other factors besides climate warming at play. However, in most cases it appears that glacier retreat is, indeed, secondary to climate change. There are a few cases of glaciers that are expanding, but that is rare and explained by the peculiar circumstances of those glaciers. In fact, it is possible to think of the glaciers as the canary in the coal mine, because they, like the birds that miners took with them into mine shafts, are early indicators of the physical effects of rising temperatures.

Unlike the polar ice sheets, which are massive, the glaciers are comparatively small and often adjacent to warmer regions of the globe. Thus, their melting is more readily apparent. The melting of glaciers integrates the effects of warming directly into visible changes, an advantage over statistical models that are complex and not so easily rendered in easily understood images.

Despite being less visible and in some ways less dramatic, in the same timeframe that Molina was documenting the conversion of glacial termini into lakes, warming trends had also begun to eat away at the most vulnerable edges of sea ice in Antarctica. Between 1995 and 2002, large sections of the Larsen B Ice Shelf collapsed (Fig. 1.2; NASA Observatory, 2002) Not long after, the Wilkens Ice Shelf also began to deteriorate. Both are on the Antarctica peninsula, the most exposed and vulnerable ice on the continent.

Fig. 1.2

Collapse of the Larsen B Ice Shelf on the Antarctic Peninsula from January to April 2002. The shelf is sea ice so more vulnerable to warming than ice on land. Also, because it is sea ice, it does not add to sea level rise. (Reproduced from NASA Observatory, 2002)

There is yet another massive storage of ice that is more difficult to see than the glaciers and polar ice. This is the permafrost, essentially, frozen ground. Permafrost is found mostly in the arctic, but also at high elevations, notably the Himalaya Mountains in South Asia which is sometimes called the “Third Pole” because of its smaller, but still considerable, ice content. As permafrost melts it has revealed ancient remains of animals and plants that have been preserved in a frozen state for millennia (Fig. 1.3; Plotnikov, 2020).

Fig. 1.3

A photograph of a largely preserved carcass of a woolly rhino that emerged from the melting permafrost in August 2020 in Yakutia, Russia. (Reprinted with permission from the Associated Press (Plotnikov, 2020))

Temperatures are rising faster in the arctic than at the Third Pole largely because the extensive cover of white ice reflects sunlight back before it is absorbed and warms the surface. Counter intuitively, ice is melting faster at the Third Pole, in part because the Arctic has boreal forests and moss coverage that the Third Pole does not.

As the ground ice melts it releases methane and carbon dioxide. An estimate of the amount of organic carbon in soil in the Northern Hemisphere is 1700 Pg, about the same amount as the water in Lake Ontario. The melting of the permafrost creates a positive feedback loop in which more melting releases more carbon into the atmosphere, driving further increase in temperatures and then more warming of ground ice and more release of carbon. (Nisbet et al., 2023).

Sometime in the fall of 2013 a massive cylindrical crater formed in the Siberian permafrost. Scientists flew out from Moscow to examine this new feature in the earth and observed that it, and others found subsequently, were formed suddenly by violent explosions that thrust soil and ice hundreds of meters. There were signs of burning at the remaining edges of the craters. (Gray, 2020).

It is now established that these craters are created by blasts of methane gas. It appears that a warmer climate is releasing trapped methane in the frozen ground that builds up and forms a mound. After the pressure in the mound becomes too great, it is released in a blast that leaves a cylindrical crater, almost as if a round cookie cutter had excised a piece of the earth (Fig. 1.4; Pushkarev, 2014).

Fig. 1.4

This picture is of a crater in north-west Siberia on the Yamal Peninsula that is 164 feet-deep (50 m). The hole formed in 2013 and apparently was created by the explosion of methane gas. (Used with permission Reuters (Alaska Public Media, 2022))

If the melting ice provides a tangible indication of the impact of climate change so far on our planet, it cannot tell us what will happen in the future. For that we need modeling. By its nature, modeling is a highly technical exercise that in its full details is virtually impenetrable for the non-scientist. All modeling shares these features, but climate modeling, because of the consequences and the inherent complexity, is even harder to explain and assess.

Perhaps a comparison to the models with which we are most familiar is helpful. We all depend on these models because they predict the weather. Weather models, as we all know, have improved over time (they were too often wrong 40 years ago) yet still retain a degree of error. Usually they are reasonably accurate, but they have limits. If one watches the prediction a week ahead and pays attention as the day approaches, the prediction changes and, usually, becomes more accurate.

Weather models are both helpful and problematic when trying to explain climate change modeling. From an experiential standpoint, they can give the reader a general sense of what models are and how they function. However, unlike melting ice, weather is a poor metric by which to observe climate change. This is because weather is, in many places, highly variable. Weather can seem, erroneously, to confirm climate change during a heat wave and challenge it during a blizzard.

Climate change models use many variables as inputs—such as temperature, estimates of carbon dioxide releases, cloud cover, geography and others—to predict changes in climate variables, much as weather models predict temperature, precipitation and wind. Climate models are usually compared to data from the past to test their accuracy. There are many climate models, each with slightly different approaches and inputs, developed by teams of researchers that result in a range of outcomes and magnitudes of error.

Too often, popular debates about climate change revolve around whether it is real, a black and white absolutism that fails to reflect the underlying science. Instead, we would urge the reader to consider that the main debate is about how fast climate change is happening because that is what affects the scale and timing of responses that are needed.

We see that climate change is an impending crisis, but compared to, for example, the Fukushima nuclear accident, it is a slow-moving disaster, unfolding over decades. Because climate change is a gradual accumulation of gasses in the atmosphere that contribute to warming and because these gasses have long lives, reversing climate change will also be slow. There is already substantial momentum forcing temperature rises that will not be possible to reverse quickly.

While tracking the changes in global temperature and observing their more obvious impacts, including changes in the ice, has some challenges, it is comparatively straightforward relative to predicting the future of climate change.

In the context of climate change, the input data and temporal and spatial scale of modeling is much larger than models that attempt to predict the weather a day or a week from now. Climate models can be global in scope and seek to predict what will happen decades from now. Thus, climate models require vast amounts of computer capacity to make calculations based on immense computer codes. Inputs into these models include solar radiation, concentrations of gasses in the atmosphere that increase temperature (such as carbon dioxide and methane) and concentrations of particulate matter in the air that reduce temperature.

No models are perfect. Therein lies the real potential controversy about climate change. Different models offer different predictions of the trajectory of climate change. Some predict that we have more time, others that we have less. If the models predicting slower change are more accurate, we have more time to adapt. However, since we cannot be certain, we think that it would be a mistake to assume the best-case scenario is correct (Fig. 1.5). If we are wrong in our optimistic assumption, we will have even less time to respond once we figure that out and the costs will be greater and the damage more severe.

Fig. 1.5

NASA prediction of global temperature increases depending on changes in CO₂ emissions. (NASA Earth Observatory, n.d.)

It is better to prepare for the worst and if that is overly cautious, there will be many ancillary benefits to burning less fossil fuel. The primary of which will be reducing ambient air pollution. Particulate matter air pollution, which derives substantially from combustion sources, is responsible for millions of deaths worldwide every year and even more serious chronic illnesses (Chang et al., 2022). Frankly, the toll from air pollution that derives from the same sources as climate change should, by itself, justify moving away from combustion related climate forcing emissions.

For our purpose in this book, time is a significant factor in terms of considering nuclear power as a response to climate change. The problem for nuclear power supporters is that in the current context, at least in highly developed countries, approving, financing and building nuclear power plants takes an inordinately long time. We will discuss this in detail in Chap. 7. Since we need to respond to the climate change threat quickly, a power source that is slow to come online is unlikely to be a viable part of our response.

Summary Points

• 1. Melting glaciers and polar ice are highly visible and reasonably accurate indicators of climate change.

• 2. Statistical models of global temperature change show consistent increases, although the speed with which warming is happening varies based on the model assumptions.

• 3. The need to move away from fossil fuels raises the question of which sources of energy are best, including the possible role of nuclear power.