Part 2 of Earth as an Ecosystem
Understanding the impact of climate change is an integral part of managing a sustainable future. From a geological perspective, Earth is currently in an unnaturally cool period, and a “normal Earth” is much warmer than today. We also know the planet is constantly in flux, and change is the norm. Our planet has experienced between five and seven mass extinction events, depending on how you count them. Historically these mass extinctions occurred through natural processes that dramatically altered Earth’s ecosystems. Today, however, the Anthropocene extinctions represent rapid environmental changes caused by a single species, Homo sapiens.
The changes wrought by humankind create existential threats to our species, and we fear those changes for good reasons. Understanding the nature of those threats requires an examination of how the relationship between people and ecosystems has evolved over the past 20,000 years.
Rise of agriculture
Approximately 12,000 years ago, Earth exited the last Pleistocene Ice Age, where glaciers covered vast areas of the planet. Climate change was rapid and dramatic, but nomadic hunter-gatherer tribes didn’t ponder climate change as a problem to be solved because they were too busy trying to survive and adapt. As the ecosystems around them changed, they migrated and adapted their lifestyles to new environmental conditions.
As sea level rose, coastal communities migrated inland, and when food sources disappeared, new food sources were found. Part of the key to this adaptation was a lack of permanence. People moved to where the food source was. Migration was a key component of survival.
The first agricultural revolution changed this dynamic. With the advent of crops and domesticated animals, communities settled into fixed locations for long periods but still maintain adequate food sources. This change gave birth to the age of cities and empires, where adequate food security allowed human creativity to flourish, producing new technologies. The rise and fall of empires didn’t extinguish the true strength of Homo sapiens, the ability to pass knowledge on from generation to generation.
The role of cities
One of the keys to understanding threats posed by climate change lies in the role cities play in our societies. We take them for granted in places like the USA and forget that 54 percent of the population was rural in 1910; but today, 81 percent of the population is urban. Traditionally, rural populations aligned closely with the ecosystems surrounding them. Food sources were local, and a community’s population carrying-capacity directly reflected the amount of food an ecosystem could produce.
But the rise of large cities broke this dependence on local ecosystems. It gave rise to agricultural systems where industrialized farms produced food products and shipped them to large urban centers. Readily available food allowed these urban centers to grow into the metropolises we enjoy today. But this process produced a system where most of our population is disconnected from the ecosystems that sustain them.
Food security
Climate change threatens this relationship between rural and urban settings when environmental changes jeopardize major food sources. So, one of the concerns with climate change is food security. But even this threat is nuanced. In wealthy countries, many people were unaware of the 2007-2008 global food crisis. Grain shortages, driven by high oil prices, increased biofuel production, weather shocks, and trade restrictions, jeopardized food supplies. Food, like other commodities, rises in value when it is in short supply. For those with ample financial resources, the 2007-08 grain shortage translated into household budget tradeoffs as more money went to food and less to other activities. But for the poor, higher prices
If climate change causes food production to falter, then rising prices take their toll, with the first to feel the impact being the poorest and most vulnerable. From a global perspective, food scarcity is one of the existential threats posed by climate change. In a world where almost eight billion mouths need feeding each day, climate changes, which alter or diminish agricultural output, also threaten social stability and the lives of the poor. Remember, approximately 3.5 billion people, almost half the world’s population, live in poverty, struggling daily to provide food and shelter. Small changes in food availability or cost have life-and-death consequences for half of the people on our planet.
Sources:
2050 and 2035: Failure and Hope for the Climate Crisis (By William House; Earthsphere on Medium) – https://medium.com/earthsphere/2050-and-2035-failure-and-hope-for-the-climate-crisis-ae8fcc4fdc4e?source=friends_link&sk=44b002976cd6a2f817707721a13c12aa
Ancient analogs show that a hotter planet is the geological norm (By William House; The Startup on Medium) – https://medium.com/swlh/ancient-analogs-show-that-a-hotter-planet-is-the-geological-norm-edd4d22d8cdd?source=friends_link&sk=3b87bc3c4f7ea42fe4bee52053ca30cd
Feature Image: Corn shows the affect of drought in Texas on Aug. 20, 2013 (Modified) – By USDA photo by Bob Nichols – https://www.usda.gov/media/blog/2014/02/11/southern-plains-climate-hub-seeks-address-three-huge-problems, Public Domain, https://commons.wikimedia.org/w/index.php?curid=89060994
