Cold weather doesn't mean climate change isn't happening: Bob McDonald

It’s hard to think about climate change while most of the country is in a deep freeze. But while this part of the planet is freezing, other parts are baking, which is why climate change requires a global perspective.

Much of Canada may be in a deep freeze, but other parts of the world are baking

Bob McDonald cautions that cold weather across much of Canada does not mean that climate change isn't happening. (Darren Bernhardt/CBC)

It’s hard to think about climate change while most of the country is in a deep freeze – the Great Lakes are almost entirely frozen over and people on the East Coast are tunnelling out of their homes. But while this part of the planet is freezing, other parts are baking, which is why climate change requires a global perspective.  

A snowball was thrown in the U.S. Senate this week by Senator James Inhofe (R-Okla.), a vocal climate change denier, in an attempt to show that the unseasonably cold weather outside is proof that humans are not making the planet warmer. What he was really showing is his ignorance about the difference between weather and climate.

The phrase “Climate is what you expect; weather is what you get,” invoked by climate scientists, means that the weather we see happening outside our windows is a short-term effect, while climate is a global average measured over a longer period of time. So to judge the planet by what’s happening in your own backyard is narrow thinking.  

While the central and eastern parts of the continent have suffered extreme cold for the last two winters, the thermometer here in Victoria hasn’t dropped below freezing at all, skiers along the West Coast are climbing to higher altitudes to find snow, many ski resorts have closed and my lawn needs cutting.

Australia is baking with record heat, California continues the longest drought in decades, Greenland continues to lose ice at an unprecedented rate and the Arctic Ocean shows more open water every summer.

Atmosphere includes hot and cold air masses

Incorporating cold into climate models is all part of the global picture. That’s why scientists abandoned the term “global warming” years ago, and now talk about climate change, because change affects both warm and cold regions of the Earth.

Our atmosphere includes both hot and cold air masses, which are always jockeying for position around the globe. Cold air is denser than warm, so it tends to be more pushy, hugging the ground in big high-pressure pools, while lighter warm air bumps into it, rises over the top, cools with altitude and drops moisture as rain or snow.

While much of Canada is in a deep freeze, Australia is baking with record heat and California continues the longest drought in decades. (Steven Hausler/ Associated Press)

It’s along the boundary between the warm and cold masses that we get storms.

Over the past two winters, the jet stream, which is that boundary between cold Arctic air and warm tropical air, has dipped south over the North American continent, allowing that big blob of frigid air to sit over the land and steer storms to the East Coast. But on the West Coast, that same jet stream curves upwards, producing what locals call the “Pineapple Express” of northward-flowing warm air.

Usually, the jet stream moves along, providing breaks from the cold during winter, but recently, it has been sluggish. Whether that's due to climate change cannot be determined yet because two years of cold is not enough to see a long-term pattern.

But a recent experiment at the Lawrence Berkeley National Laboratory in California has directly measured the warming effect of our carbon emissions, using data from instruments that measure the infrared radiation being reflected back to the ground by the atmosphere - the so-called greenhouse effect.

Measuring effects of carbon emissions

They found that the amount of radiation coming down increased between 2000 and 2010 in step with the rise of carbon dioxide in the atmosphere. So, the effect is real. And since we are continuing to increase our carbon emissions, change will continue to happen, like it or not, both warm and cold.

Interestingly, one solution to this problem will be demonstrated next week, as Solar Impulse takes off from Abu Dhabi, U.A.E, on the first solar-powered round the world flight.

The aircraft is capable of circling the globe non-stop, including flying at night, without using fossil fuels. Instead, Solar Impulse will take six months to complete twelve flight segments, stopping in various countries for educational tours, demonstrating the potential of clean alternative energy.

So, you could say that this is a case where, if we really don’t like the weather, we could do something about it - by not changing the climate.


Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.