If we continue to act in our business as usual ways, we may be putting Earth at risk for sudden, very major changes.

Today, I heard Lance Gunderson, the chair of Emory’s Environmental Science Department, address various factors influencing global environmental change, the role of humans in these shifts, and the best strategies for understanding these changes through systems models.

What stood out to me most about the lecture was the consideration of Earth system science in global environmental change. In this way, Earth is a system, or a holistic view of an interacting set of components that form a unified whole. It involves many ‘spheres,’ including the atmosphere, hydrosphere, geosphere, biosphere, cryosphere, and lithosphere. By simplifying these complexities and studying the dynamic behaviors and trajectories of Earth’s systems, we can attempt to better understand the directions Earth is heading towards. 

Earth has many spheres that interact in a holistic system / Earth / Kevin Gill / Creative Commons Flickr Images

And understanding these trajectories is key to ensuring that humans do not drive Earth to cross any unforeseen thresholds. An environment may remain static until a threshold is reached, at which point consequences will begin abruptly and rapidly. Ocean acidification, for example, may have little effect on coral until a threshold is reached, at which point coral reefs will begin to experience bleaching on a large scale. These were all ideas that Dr. Gunderson referred to as he described the concept of planetary boundaries. 

When I attended and observed COP23, I heard many people discuss the importance of the precautionary principle. Now, I better understand why. A planetary boundary framework can provide us with the guidelines we need to lessen the impact of humans before we reach negative, potentially irreversible consequences for Earth. We have already reached crossed three thresholds; now, our goal should be to prevent crossing even more.

But how can we determine these thresholds? How can we calculate and quantify thresholds in order to guarantee that we take all measures possible to not reach these points? These are the questions we need to ask if we want to mitigate climate change rather than further exacerbate it as we currently are.

A huge theme of Dr. Gunderson’s presentation surrounded the uncertainties of these thresholds and the need to focus not just on what we know, but also on what we do not yet know. Some of the planetary boundaries are not yet quantified, and others still hold uncertainties. It’s difficult to plan and estimate planetary boundaries due to the complexity of Earth’s natural systems and our current lack of knowledge of the nature of biophysical thresholds.

But regardless of whether or not we can quantify these thresholds, there is no harm in mitigating climate change before we even get close to these points; if we take necessary precautions now, we can ensure that Earth’s environment is stable without further approaching any unknown limits. 


Dr. Gunderson presented two videos during his lecture to help visualize the environmental changes that have been occurring on Earth:   



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