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Global warming means even more rain in January for Vancouver

January weather is changing in Vancouver. If you’ve been hoping that climate change would bring us lots more rain, you’re in luck.

January is bringing Vancouverites lots more rain, half as much snow, rising temperatures and new high-energy weather extremes. That is according to my analysis and charting of seventy five years of Environment Canada weather records.

These are exactly the overall trends that climate science says will continue in BC and worldwide, until we stop turbo-charging our weather with fossil fuel pollution.

Fossil fuels increase rainfall

Every year we spill billions of tonnes of CO2 from oil, coal and gas into our atmosphere. This CO2 traps huge amounts of extra energy from the sun, causing our air and oceans to become warmer and more energetic. The extra energy in warmer air allows it to carry more water vapour and power larger storms. The result is more rain overall. (See “NASA: It rained so hard the oceans fell” and “Extreme rains rip apart historic Cinque Terre”).

As a bonus, climate models predict that more of that extra water vapour will turn to springtime clouds in our region, making our springs gloomier. (See “Spring forecast: increasingly cloudy...for decades”)

As a double-special bonus, climate science predicts a global decrease in gentle rainfall and an increase in extreme downpours. Sure enough, studies have shown this is already happening.

Dr. Kevin Trenberth, head of the Climate Analysis Section at the U.S. National Center for Atmospheric Research, explains:

“there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago…it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. “

A common rule of thumb in climate science is that global warming causes dry places to become ever drier and wet places to become ever wetter. That “getting ever wetter” part applies to us in soggy Vancouver. But hey, according to our weather data we are only getting rainier in the nine months of late fall, winter, spring and early summer. Sorry, that includes July already growing much rainier as well. But we do still have August, September and October to dry out.

So next time you hear about projects to dramatically increase fossil fuel pollution, like adding tar sands pipelines,  increasing coal mining and doubling jet traffic, grab your umbrella. You are going to need it.

Vancouver’s rainfall is changing

Here in our fair city of Vancouver, January is getting rainier. Not only is the average amount of rainfall increasing, but new extreme rainfall years are emerging. For example, as you can see in the top chart, January 2006 broke all records when 284mm of rain fell on us.

Here is another chart showing the rainfall averaged across two decade chunks. This view removes the noise of year to year variability and helps show the relentless underlying climate trend:

Vancouver’s temperature is changing

As mentioned, warmer air is more energetic and so can hold more water vapour. Climate models have long predicted that BC would experience warmer air during winter. Sure enough, measurements show winter warming is happening in dramatic fashion.

The wholesale slaughter of BC’s pine forests by our native pine beetles has been one of the more obvious consequences of it. (See “Half of BC pines dead from fossil fuel pollution. Is it over?”). As the people of Burns Lake are finding out, when fossil fuels kill off whole forests the economy and jobs that go with those forests can disappear quickly.

What about here in Vancouver? Has it also been getting warmer in January?

You bet. Here are the charts showing the average low, mean and high temperatures for January:

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