What is climate change really? And what does it mean for us Portlanders?

By Sophie Feldman ‘20

 I have found myself having many conversations,with people both within and beyond the Catlin Gabel School (CGS) community, about fears surrounding climate change. They are concerned about the state of our planet, and eager to ease their anxieties by discussing solutions. I embrace these conversations, if not for the selfish desire of easing my own existential angst, but since taking the Climate Change Palma Seminar, which began with a crash course in climate science, I have come to realize that the cold hard facts of climate change are not always clearly grasped. 

In order to begin to come up with solutions to escape the hole we have found ourselves trapped in, I think it is important we first begin to understand exactly how we found ourselves here in the first place.  I firmly believe information is power (though surely not bliss), and that the more informed you are about an issue, the more self-advocacy and changemaking can occur. 

The Basics

Feedback Loops 

When looking at climate science, the single most important concept to comprehend is a feedback loop. According to The Albert Team, feedback loops are “a biological occurrence wherein the output of a system amplifies the system (positive feedback) or inhibits the system (negative feedback).” Negative feedback loops are self-regulating while positive feedback loops produce exponential growth.

A feedback loop is an ongoing cycle, where one thing propels or halts the next, and either that propelling or halting creates further propelling or halting which will spiral the system in one direction. As time passes and the feedback loop continues, it becomes more or less of something, and increasingly difficult to reverse and bring back to its original state before the initial occurrence. Let’s break that down.

Say you are assigned a major project — you have a little less than a month to complete it. It’s a daunting task, so you decide to give yourself a week before you start working on it. The next week, you’re overwhelmed as you are now left with only two weeks rather than three, so you wait. Eventually you find yourself a few days before the deadline, panic at an all-time high. The more you waited on your project, the more overwhelmed you became, and the less likely you were to get it completed in a timely and well-done manner. Procrastination is a dishearteningly relatable feedback loop.

As you will see, feedback loops are instrumental in pushing climate change along, though it is important to note that there are also powerful negative feedback loops at play that are minimizing the effects of climate change. Below I have outlined the feedback loops I deemed most important to understand how climate change is occurring. There are many more feedback loops related to climate change that I have not described, including but not limited to desertification, solubility pumps, and planck feedback.

The Greenhouse Effect 

The Greenhouse Effect is the process in which solar radiation from the sun enters the atmosphere and bounces back into space after being reflected off of the earth’s surface or cloud coverage. The earth’s surface absorbs the radiation, and is thus warmed, then reflects back that radiation at a lower energy level. 

The exit process is less straightforward, as the long-wave radiation headed away from the earth’s surface back into space is met with greenhouse gases, which are heat-trapping compounds. Some of that radiation escapes and is released into space, but some is absorbed by greenhouse gases and re-emitted in all directions, including back to earth. Therefore, the heat energy is distributed differently. Instead of being spread out across the different atmospheric layers, it is condensed in the lower troposphere, close to the surface, where more heat is retained.

As we continue to emit carbon dioxide, we are adding more greenhouse gases to the system and amplifying the Greenhouse Effect. This system most plays into the earth’s net warming.

Diagram of the Greenhouse Effect. Via Wikimedia Commons

The Albedo Effect

The Albedo Effect is the process in which snow and ice melt as the earth is heated. Ice has a high albedo, meaning it reflects more light on the visible spectrum. Ice has a reflectivity of 0.9 while water only has one of 0.1, meaning ice reflects 90% of the radiation that hits it while water reflects a mere 10%, absorbing the remaining 90%. 

When glaciers melt, they expose more land. The land has a lower reflectivity and can absorb heat which increases the earth’s temperature. Not only is more land exposed, but more water, which has a lower reflectivity, is created as the ice melts, meaning more heat is absorbed. Thus the earth is increasingly heated once ice is melted and the cycle continues.

This feedback loop is the cause of the sea level rise we are experiencing.

Expected flooded areas per foot of sea level rise in Portland, OR, at 2, 5, and 10 feet. Via Sea Level Rise Viewer.

 Ocean Acidification

Ocean acidification is a result of the carbon dioxide we are adding to the atmosphere, which dissolves into the oceans. Through a process of chemical reactions, that carbon dioxide leads to a lowering on the pH scale, meaning towards acidity. So far, there has been a decrease in the ocean from 8.2 to 8.1, but because the pH scale is logarithmic rather than linear, meaning each value along the number line has a difference of a multiplicity of 10 from the next, that 0.1 change is a dramatic one.

A breakdown of ocean acidification for you chemists. Via Northeast Coastal Acidification Network.

According to UNESCO, the United Nations Educational, Scientific and Cultural Organization, ocean acidity has increased by 30% since the beginning of the Industrial Revolution, and the ocean is projected to become 150% more acidic by 2100 if our patterns of behavior are unchanging.

As we add carbon to the ocean, we’re interfering with the chemical processes that allow for mollusks, corals, pteropods, and many other microorganisms to build shells. As more and more of these microorganisms struggle to survive without nature’s protection, we are wreaking havoc on marine ecosystems as the bottom of the food chain collapses. Ocean acidification also weakens the skeleton of coral reefs, an ecosystem which is essential to maintaining marine biodiversity as it acts as breeding grounds to a great deal of commercial fish life.

Changing Skies

Changes in Precipitation 

Staying true to the term “global warming,” heat waves are anticipated to occur with more frequency, more intensity, and for longer periods of time. In addition to increased heat waves, which will cause droughts, there will also be an increase in flooding. This is a point of confusion among the public and a fact that is wielded by climate deniers. 

While the increased heating of the atmosphere leads to further evaporation, and thus drought, that evaporated water is stored as water vapor in the atmosphere. Scientist Kevin E. Trenberth wrote in a paper that “the water holding capacity of air increases by about 7% per 1°C warming … hence, storms … supplied with increased moisture, produce more intense precipitation events.” 

Climate change will not simply cause net warming, though the trend is an overall increased temperature. It will cause changes in precipitation patterns, in the distribution of water, simultaneously causing more droughts and floods — more erratic weather patterns altogether.

Hurricanes

The growing number of storms and other natural disaster events are another point of misinformation. Hurricanes are the result of thunderstorms when the winds are spinning just right, meaning winds that blow gently higher up in the atmosphere and winds that blow more strongly near the surface of the earth. They always begin over an ocean, and the ones we experience in the Eastern United States generally begin off the coast of Africa. A large bulge of warm water is drawn up from the ocean’s surface and pulled into the atmosphere. This water becomes the storm surge, or the “eye of the storm.” As the water becomes warmer, it condenses and creates heat, which rises and forms an inward swirling air column which rotates around a low pressure center. The hurricane will move across the ocean with winds of at least 72 miles per hour and heavy rainstorms, gathering more heat and water in the storm surge.

The hurricane must always maintain its momentum, otherwise it will become undone and become a simple thunderstorm once more. A strong wind in the upper atmosphere is a hurricane’s kryptonite. Disastrous examples of hurricanes in the recent past include Hurricane Harvey and Hurricane Katrina.

Hurricane Katrina over the Bahamas on August 23, 2005. By National Oceanic and Atmospheric Administration satellite image.

Hurricanes are fueled by high sea surface temperatures (water warmer than 26.5 degrees °C), and as the feedback loop of The Greenhouse Effect is amplified, sea temperatures will rise. Hurricanes cannot be directly correlated to climate change, though some natural disasters can be. For hurricanes, when they occur, they will be much more powerful and be prolonged by the readily available oceanic heat.

“I think we are too hopeful. We have about ten years to continue emitting as we do before tipping into irreversible feedback loops, and surpassing internationally accepted targets. When I created a zero carbon plan for the United States, one of the world's biggest emitters, that would take place over the next ten years, beginning immediately, I realized that even with full support, reaching net zero carbon emissions in ten years would be extremely difficult, and there definitely is not enough government support for that to occur. Many countries are aiming for net zero emissions by 2050. That is simply too late,” wrote ninth grader Chloe Jahncke in a survey sent out to Catlin Gabel Palma Seminar students.

So What Next?

Climate modeling is imprecise; there’s no denying it. The Butterfly Effect, a term coined by American mathematician and meteorologist Edward Lorenz, explains that miniscule changes will have unpredictable effects, as any system with three or more particles is inherently chaotic: “The flap of a butterfly’s wings in Brazil could set in motion atmospheric events that lead to a tornado forming in Texas several weeks later. Since we can’t possibly know precisely what every butterfly will do, we can’t precisely predict the future.” 

Despite the Butterfly Effect, climate modeling can give us a good estimate at what the earth will look like if our net warming continues, though they can’t pinpoint exact dates. And to be clear, the global changes have begun.

Attorney and teacher Alex Williamson. Courtesy of Alex Williamson.

Resident climate change expert Alex Williamson, who is teaching the Climate Change Palma Seminar this year, spelled out these changes: “We’re on track for something in the neighborhood of 4 degrees celsius increase over pre-industrial temperatures, so about 3 degrees celsius more than we’ve seen so far … you’re looking at a couple meters of sea level rise bare minimum, depending on how Greenland and the West Antarctic ice sheets respond to these feedback loops. If it goes poorly, then we’d be looking at tens of meters of sea level rise, which would take out a pretty significant portion of the most populated places on earth.” 

Williamson studied environmental law at Tulane University. Then, fresh out of law school, he worked on a groundbreaking climate case that allowed him to “personally cause the fossil fuel industry millions of dollars in attorney fees” — a point of pride for Williamson.

What about Portland?

The sea level rise, anticipated to be between a couple meters to tens of meters, will flood Oregon’s coastal and low-elevation regions. In Portland, “we’d see climatic shifts to become more and more Mediterranean in our microclimate —  drier, warmer, more drought-prone,” Williamson forecasted, noting that “the big concern here in Portland would be water supply. We get a great deal of our water from snow melt in the mountains and a four degree warmer world just has much less snow accumulation in the mountains year to year,” so permanent drought conditions will be our most pertinent concern.

“What would Portland look like if it had Los Angeles’s climate?” asked Williamson in efforts to describe Portland’s future microclimate. Brown dry hills and scrub trees come to mind, possibly some cacti. “They would not be the big leaf maples and western hemlocks [of today] – it’s a very different Portland 100 years from now in a four degree change.”

The Younger Dryas Event and Possible Re-creation

The other possibility? Extreme cooling. 

Between 12,800 to 11,500 years ago during the Pleistocene epoch, the earth was in a period of warming, so many glaciers began to melt, as they are now. A huge glacier off of Greenland melted in this wave, but as glacier water is freshwater, meaning it is less dense than salt water, it sat atop the other water. 

Ocean currents are immensely complicated and are thus hard to predict, but the result of this melt was that the freshwater acted as a plug on the Atlantic Ocean’s thermohaline cycle. “Weather is dependent upon how the oceans move warm wet air around and an increase in melt water interferes with the thermohaline cycle,” explained Williamson.

Normally the current would bring warm, moist air to Northern Europe, “which is why the UK is temperate while London is on a similar latitude to Anchorage,” said Williamson. This warm air wasn’t making it past the plug, which allowed for glaciers to advance from the North. Essentially, the microclimate of the UK was transformed into that of Alaska. Until this melt was dispersed, which took a couple hundred years, the North American and Northern Europe experienced a rapid decline in temperatures, which resulted in glaciers advancing southwards. Once the currents had returned to their prior state, the initial warming resumed.

As the increase in global temperatures continues to melt glaciers, a re-creation of the Younger Dryas Event seems to be a possibility, depending upon the rate at which glaciers melt and the variability of oceanic currents. In this case, the warming we are experiencing would slow, but we could be faced with the challenge of glaciers quickly advancing into Northern Europe and North America. The agricultural industry on these continents could shut down for a couple hundred years, placing a huge strain on global food sources. 

The glaciers would be expected to advance all through Canada and into parts of Washington, so Portland’s microclimate could become a cold tundra. Think snowy barren land, cold winds between -34 to -6 degrees celsius, mountain goats, arctic foxes, musk oxen, snow geese, and low-lying plants and insects with a brief bloom of wildflowers in the summer. 

It may be that atmospheric carbon dioxide concentrations are high enough to keep the glaciers at bay, so we might only see a slight southward drift. Much about this possibility has yet to be determined.

 A Final Thought

Either way, the possibilities are a daunting reality. So please, keep this in mind as you go about your day and make environmentally conscientious choices. It’s our Portland, our Oregon, our planet, and the only one we’ve got. Let’s take good care.