Environmentalism and Climate Change in a Total Earth Context
We grapple daily with environmental and climate change issues ranging in scale from microbial changes in soils to vast islands of plastic polluting our seas. Massive forest fires, melting ice sheets, and devastating hurricanes capture the headlines, and it is easy to forget how interconnected our world is. Photos of our planet, taken from afar, remind us of the big picture—life on Earth is a single web of life. At the highest level, Earth’s surface forms a connected planetary-scale ecosystem—one that has taken over four billion years to evolve.
As a refresher, an ecosystem is a group of interdependent biotic and abiotic components that function together as a sustainable unit. Importantly ecosystems are often nested. The Tongass temperate rain forest forms an ecological community intimately connected with the marine ecosystems of the Pacific Ocean. Together these two ecosystems form a larger coastal ecosystem. The Cascade Mountains of Oregon are home to temperate rain forests on their western slopes and high deserts on their eastern side. These two distinct ecosystems connect at the hip via a high mountain range, which controls rainfall.
Our planet’s surface is an interconnected web of life—a master ecosystem with multiple smaller systems nested inside. At the smallest scale, individual ecosystems are the basic units of our environment. Therefore, environmental health in a region is measured by the health of its component ecosystems. At a fundamental level, climate change presents itself as changes in local and regional ecosystems. Higher global temperatures, for example, deplete precious moisture reserves in areas like California and lead to longer, more intense dry seasons. Dryer, hotter conditions then set the stage for larger and more damaging wildfires.
In our efforts to combat climate change, we shouldn’t lose sight of the ultimate goal, which is maintaining a sustainable planetary ecosystem where humans can survive and thrive in balance with the local ecosystems surrounding them.
Life in Flux
Life is always in a state of flux and change, so the goal is not stasis or a return to the past. The objective of tackling climate change is to create a dynamic and sustainable balance between humans and their environments. We depend on healthy ecosystems for our continued survival. Destroy the microbe-laden humus in the farmer’s soil, and crops will fail. Put too many nutrients or toxins into our estuarine hatcheries, and our offshore fisheries will disappear.
The greatest geographic division of ecosystems on our planet is between terrigenous and marine environments. But both of these domains are affected and connected by the single most visible driver of Anthropocene climate change: global warming. The atmosphere provides this connection through its incorporation of carbon dioxide (CO2) from fossil fuel emissions.
The accumulation of greenhouse gases in the atmosphere directly ties to a proven rise in average global temperature over the past 100 years. Temperature is one of the defining environmental conditions affecting ecosystems on land and in the sea. As temperatures change, so do ecosystems.
But in our oceans, global warming does more than just increase temperatures—it also increases ocean acidity. Oceans cover about 71% of the surface of the planet. Where the ocean and atmosphere meet, they interact and exchange carbon dioxide (CO2). The Earth’s current CO2 budget dictates that when CO2 enters the atmosphere from burning fossil fuels, only about 45% of the CO2 stays in the atmosphere. Land plants use about 25% of the emitted CO2, and then the oceans absorb the remaining 30%. Since colder water absorbs more CO2 than warmer water, polar oceans are more significant reservoirs for CO2 than tropical waters.
Carbonate buffering is the name given to the CO2 exchange process between the atmosphere and the oceans. When CO2 enters the ocean, it reacts with water to form carbonic acid, and this causes ocean acidification.
The effects of ocean acidification start at the bottom of the food chain. Higher acidity decreases the amount of calcium carbonate available for small planktonic creatures to make their shells. Groups like pteropods are an important planktonic component at the base of the food chain. Without the plankton, the ocean ecosystem collapses. If plankton can’t produce viable shells because of increasing acidity, then the species won’t survive, and the ocean’s fish populations dependent on those plankton will decline.
Earth is a single planetary-scale ecosystem, and changes in one part of that system will inevitably affect the whole system to one degree or another. Managing climate change has many aspects, but don’t lose sight of the overall prize: A healthy, sustainable biosphere.