The mega-consequences of a mega-drought
Water service providers are very familiar with the trials and tribulations caused by drought, and have a wealth of experience in dealing with periods of little rain. What happens, though, at times of extreme drought?
At Ozwater’21, Russell Beatty of Hydrology and Risk Consulting considered the importance of putting plans in place to allow utilities to respond to such an event in an orderly and systematic way.
“We are at the moment in a relatively dry period,” he told the delegates. “But, in actual fact, if you go back a thousand years, you can see periods that were similar or drier than the current climate.”
That is because the planet goes through long-term periods of climate change.
“Climate change is very real, but I’m not talking about human-induced climate change related to carbon dioxide emissions,” Beatty said.
“We’re talking about natural cycles that we probably don’t really know much about what’s actually happened in those circumstances and what’s driving those circumstances.”
The likelihood of experiencing an unexpectedly extreme drought is quite low, but the consequences could be very high, Beatty said, which is why it is important to prepare plans that are well-defined and include specific actions.
The effects of this can be seen historically: a thriving Native American community in Colorado that disappeared roughly 500 years ago, or Viking settlements in Greenland that were able to survive until the climate cooled.
In Australia, there is also evidence in the pre-instrumental record of major changes that climate has had on settlement patterns over time.
“We’re talking about natural cycles, which in some ways, for a shorter period of time, dwarf what we might see from the anthropogenic side,” Beatty said.
“It’s really important to understand that these things can happen.”
This is a different problem to human-caused climate change, he clarifies. Climate change resulting from carbon emissions can be anticipated, it arrives gradually, and can be prepared for.
The type of climate shift that might cause an extreme drought, however, is much more difficult to anticipate.
“We get to really draconian levels of water restrictions, and we keep the water system going because we have to get water throughout the city,” Beatty conjectured as an example of the hardship an extreme drought could bring.
“So we have limitations on personal bathing, we’ve got shut down of automatic flushing of toilet systems; we could get really quite nasty, but we’ve still got water leaking in the system, so we say work from home if possible — which we’re used to now because of COVID — but this is the picture of what it could look like. It’s not pretty.”
The consequences of a complete shutdown could be even more wide-ranging and severe. In the case of a full supply failure of water to a region, for instance, these could include a loss of a substantial proportion of GDP for the supply area.
Emergency supply costs related to water carting or providing emergency supply infrastructure; manual water distribution costs; evacuation costs; income support; and special law and order provisions and enforcement.
“There is a systematic process you can go through and start planning for how we can avoid that situation — because it must be avoided,” Beatty said.
“A mega drought has the potential to be a much bigger problem than anthropogenic climate change if it occurs, and currently planning doesn’t typically tackle the issue in a meaningful way.”