Les Leyne: Climate change brings water worries

Les Leyne mugshot genericThe award for long-range thinking at this year’s Union of B.C. Municipalities convention goes to those involved in the seminar devoted to adapting to climate change.

They should wait a hundred years for the trophy presentation, because it’s subject to actually executing some of the ideas that were discussed by a panel.

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The headlines for years have been about the “fight” against climate change and all the decisions around mitigating it. But the story behind that story doesn’t get the same amount of attention.

It’s about adapting to climate change. It looks to be happening regardless of how the fight goes. The projections of temperature increases usually include three guesses — an apocalyptic rise if nothing is done, a moderated increase if mitigation targets are met and a smaller rise if more aggressive targets are set.

But all three projections have average temperatures going up. There’s a lot of work going on behind the scenes on how to brace for the impacts.

The expectation is that, whatever the international accords accomplish, it’s going to keep getting warmer. The UBCM panel concentrated on what that means for the most crucial aspect of life — water.

“Straight Talk on Weird Weather” was the title. The weirdness factor boils down to evidence — based on rainfall, snowpack, river flow, evaporation and soil-moisture rates — that the seasonal ups and downs are getting more extreme. The snowpack over much of B.C. is consistently less than normal. B.C. rivers are running much higher than normal in the spring and much lower than usual in the summer.

The climate has changed over the past several decades, and the most noticeable effect is in the extremes. Generally, it’s getting hotter and drier in some seasons and wetter in others. The south coast is getting wetter autumns, warmer springs and warmer winters. Locally, the projection is for 20 per cent less precipitation on the south Island by 2050.

Trevor Murdock of the Pacific Climate Impacts Consortium said the extreme coldest years by the end of the century would actually be warmer than the temperatures being recorded today and in the past 15 years.

What it means to a lot of towns and cities is an increased chance of flooding, which the city of Vancouver is starting to get its civic mind around. It raised its minimum construction elevation in exposed areas by a metre two years ago. But the prospect of a one-metre rise in sea level by 2100 entails a lot more than that.

The principles involved in coping with that centre on three options: adapt to it, protect assets from it or retreat from it.

The last one is the most extreme, since it would involve abandonment of the highest-value assets on what is usually the most expensive real estate. So adaptation and protecting are likelier outcomes. We don’t hear much now about “sacrificial first floors,” designed to fill up with water with minimal loss of value, but the phrase could become a lot better known in a few decades.

On the flip side, drought might also be in the cards. Anna Warwick Sears of the Okanagan Basin Water Board said B.C. is entering a period of greater risk of dry weather, while economic and population growth is steadily increasing demand for water. Generally, whenever water supply is increased without managing use, demand just rises to meet supply.

Sears’ long-range outlook sees the need for a big increase in irrigated agriculture to maintain food security and steady increases in demand due to population and industrial growth.

“The absolute cheapest, safest, fastest way to expand supply is to stop wasting water,” she said.

There are water-distribution systems in B.C. where 60 to 70 per cent is wasted through leakage. Comprehensive metering helps deal with that, but is a controversial topic in many communities.

It’s a future of steadily more unpredictable precipitation, likely much more expensive metered water and routine mandatory curtailments in frivolous usage, such as lawns.

Water supply depends a lot on weather predictions. Said Sears: “We used to plan based on what happened in the past. We can’t do that anymore.”

lleyne@timescolonist.com

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