A few months ago I had the equivalent of a science education “mini-rant” in Forbes. I thought about K-12 class lessons about the water cycle, and the glaring omission in all of them. If you are old enough to read this article, you likely were taught about the water or hydrological cycle in a very unrealistic manner. There were no human impacts in it. This month the United States Geological Survey (USGS) fixed that by debuting a new water cycle diagram with humans in it.
Updated water cycle graphic with human activities
In my previous essay from May, I noted, “Sitting in a meeting yesterday watching extremely high rainfall rates from an unnamed tropical system passing through Georgia. As the rain hit the parking lot, some of it rushed to drains while portions of it pooled on the surface.” In that moment, over two decades of my research on precipitation and flooding flashed before my eyes. As I stared out of the window at the rain flowing across the paved lot, it was clear to me that the water cycle most K-12 students were learning was not representative of what actually happens with humans around.
HOLMFIRTH, WEST YORKSHIRE, UNITED KINGDOM - 2021/01/20: A car seen splashing water as it moves on a ... [+]
Earlier this month, the USGS announced a new water cycle diagram. Their press release stated, “The revised version replaces one used by hundreds of thousands of educators and students internationally every year since 2000....This depiction brings humans into the picture, showing the water cycle as a complex interplay of small, interconnected cycles that people interact with and influence, rather than one big circle.”
The new diagram (graphic above) includes enhanced runoff associated with urban impervious surfaces, human water use (industrial, municipal, domestic, grazing or agricultural), and human-constructed reservoirs. This is an amazing upgrade, and I encourage educators to immediately adopt it for their water cycle lessons.
The O.B. Curtis Water Treatment Plant in Jackson, Mississippi on March 24, 2022. The city shut down ... [+]
As wonderful as the new graphic is, the scientist in me thought about what is missing. Here is a list of additional things that could have been included:
- Reduced infiltration due to urban impervious surfaces
- Modification of cloud and precipitation processes due to anthropogenic aerosols, urbanization, irrigation, deforestation and other land use
- Enhanced ice melt due to black carbon aerosols (soot) in the cryosphere
- Accelerated water cycle components due to greenhouse gas-related warming.
By the way, these omissions are not a complaint. I am thrilled with the new USGS graphic. They are simply a reflection of contemporary research at the intersection of human processes and the water cycle. I agree with USGS Director David Applegate who said, “This updated water cycle diagram will set a new international standard for how we visualize and communicate water’s complex journey on Earth, with the potential to better inform our next generation of scientists, natural resource managers and policymakers as they tackle the increasing challenge of sustainable water-resource management.” It also reflects something that I realized as a scientist and scholar years ago. The coupling of human and natural systems is inevitable and requires that we teach it that way.
Soot impacts melting on ice sheets
