The roads not taken

In the previous entries in this series, I developed a framework to help readers think beyond the common mantra of climate change: that temperatures will rise, it will rain harder, and floods and droughts will increase.

My goal is to highlight some of the critical junctions along the many paths into our climate future. I think of it as a trail guide into a climate wilderness that is both familiar and alien.

At those junctions one of two things can happen. If you are a planner, you face a choice: Do you plan for wet or dry? To plan thoroughly, imagine you are organizing a vacation or an outdoor wedding. It’s always wise to have contingencies for any possibility.

As an example for climate paths, let’s say you live in North Carolina, where you experience infrequent snow. In a warming climate, snow will become less common there. Thus, it would be reasonable to de-emphasize snow in wintertime planning scenarios. In the next 10 years, it might be unwise to eliminate snow from the plans altogether, but in 30 years, such a move might be defensible.

Focusing still on winter, let’s consider the abundant moisture provided to North Carolina by the warming waters of the Atlantic Ocean and the Gulf of Mexico. More extreme precipitation is certain in the future, and it’s likely we’ll continue to see winters with increased total precipitation. These are conditions for flooding. Therefore, we can justify planning scenarios that represent the mechanisms of flooding.

Such wet scenarios depend on weather patterns that transport moisture into the region. Historically, wet and dry weather patterns have occurred, so we should expect each pattern going forward. For some applications — agriculture, for example – significant wintertime drought could be a factor.

However, based on observations of what is occurring now, a mayor is justified to fund more investment to prepare for floods than droughts in the next few decades. With the fast-warming climate, during that time span, government officials and civic planners would be wise to develop plans for the next 10-30 years.

In the storylines I just described, the warming climate is tilting things away from historical patterns. Temperatures are now higher, snow is declining, and conditions trend wetter than drier. Intensity of precipitation will increase, and flash flooding will be more common.

The storyline becomes more nuanced in a place like Michigan, where we still experience freezing temperatures. As time passes, it’s more likely we will be close to the freezing point rather than safely below it. This sets a new stage regarding precipitation. There will be heavy rain, an increased likelihood of freezing rain, and the occasional record snowstorm. Winter flooding will be more likely, and with the replacement of snow by rain, the seasonal cycle of streams, lake levels, and ground moisture will change.

Ground conditions

Flood, drought, fire, and storm damage are inextricably linked to the planet’s surface conditions. These conditions have historical precedent, and all should be expected to occur in the future. However, their characteristics also will change.

Conditions on the surface are essential to any storyline providing usable planning scenarios for climate change. As we approach splits in the path and assess our options, there are two conditions we must consider: the fundamental background changes that come from the warming climate, and the changes to landscape over which we have direct influence.

Background check

The warming climate causes changes to the planet’s surface that have profound consequences on weather, as well as weather’s effects on humans and ecosystems. One can observe the most present change along Earth’s coastal areas. Sea levels are rising, and the rate of rise is accelerating. We will measure that rise in feet, not inches, over the next few decades. Aside from the slow, direct flooding from rising seas, we also have witnessed the immediate effects of storm surges.

As for large bodies of fresh water like the Great Lakes, we expect to see changes in lake levels and increased variability in lake levels for the next one to three decades. We’ll also see record-high lake levels more frequently than before.

For anyone living on the coast of a large body of water, that water’s surface should be a key consideration in your climate-planning future.

In regions around the Great Lakes, and common to northern locations, changes in ice cover also will produce extensive impacts. With less winter ice, lake evaporation will create more precipitation. For Lake Erie, it is prudent to prepare for scenarios in which intense lake-effect storms will impact urban infrastructure. The northernmost Lake Superior will still see air temperatures below freezing, so we can expect more snow from the increased evaporation.

As the seasons change, we also must consider the drying of the surface and evolving fire conditions. Fuel potential increases with more dried grasses and trees. The drying surface also challenges the water supply and limits our ability to cultivate plants and animals and manage ecosystems.

Managing the landscape

When we read about the devastating effects of weather and how the warming climate is changing our world, most coverage reflects damage to humans and the built environment. In many cases, the damage is extraordinary not “because of” climate change but because we have chosen, unwisely, to build without adequate consideration of the landscape.

We alter the planet’s surface with pavement, deforestation, and agriculture. These modifications affect the availability and flow of water. More directly, we build in flood- and fire-prone locations where the warming climate intensifies our risk. We over-allocate water in our rivers and over-pump water from the ground.

Today’s weather disasters reveal specific vulnerabilities that we can address. They tell us how water will flow and how fire will spread. Each disaster tells us how to better protect what we have built and allows us to consider climate change as we recover.

Remember: We do have leverage over climate change. Zoning, planning, design, and engineering are tools for adapting to a changing climate, and we should use them accordingly. Managing trees and open spaces allows us to protect power lines and reduce catastrophic fires.

Well-grounded

When incorporating local surface conditions into climate planning, we can simplify the scenarios we expect to face. We can focus on “What is most important to me, to my community?”

Then we narrow the questions we should answer. If we invest billions of dollars into a city’s stormwater drainage system over the next 15 years, should we not account for the extreme precipitation that is more and more likely? Do we continue to build — and rebuild — on our changing coasts? Or do we move inland?

This column can only suggest the roles the planet’s surface plays in a climate planning scenario. But if you look around at your place, it helps us personalize climate change and motivates us to take action.

In my next column, I will write about living on the edge.

 

(Lead image: A powerful atmospheric river streamed toward the U.S. Pacific Northwest in early December 2023. The long current of water vapor delivered warm, wet weather to much of western Washington and Oregon, toppling daily rainfall and temperature records and escalating flood and debris flow risks. NASA Earth Observatory image by Lauren Dauphin, using GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFC.)