Climate Change and Recent Extreme Events

According to the Conversation’s article, “Extreme heat waves in a warming world don’t just break records – they shatter them”, the summer is not quite over yet in the northern hemisphere. Still, we already see several extreme events worldwide; the record-breaking heatwaves hit the Pacific Northwest in June 2021, bringing high temperatures of 116 °F (46.67°C) in Portland, 9 degrees above its record before the heatwave.

In July, we have these extreme weather events:

• intense flooding in Germany and Belgium that killed more than 200 people,
• the massive wildfires in Oregon,
• enormous flooding in Central China, and
• severe floods in New Zealand due to very heavy rains.

A leading publisher of research-based news and analysis, Conversation, mentions:

“A couple of things are important to understand about climate change’s role in extreme weather like this.

First, humans have pumped so much carbon dioxide and other planet-warming greenhouse gases into the atmosphere that what’s “normal” has shifted. A new study, published July 26, 2021, for example, shows how record-shattering, long-lasting heat waves—those that break records by a wide margin—are becoming increasingly likely and that the rate of global warming is connected with the increasing chances of these heat extremes.

Second, not every extreme weather event is connected to global warming.

A study published in July 2021 shows that record-breaking heat waves will become more frequent due to global temperature increases.

The article discusses the bell curve shifting. Like many other things, temperatures also follow a bell curve shift. The bell curve or “normal distributions” are also happening.

It added:

“The most frequent and likely temperatures are near the average, and values farther from the average quickly become much less likely. All else being equal, a little warming shifts the bell to the right – toward higher temperatures. Even a shift of just a few degrees makes the really unlikely temperatures in the extreme ‘tail’ of the bell happen dramatically more often.”

Does climate change have a role in these extreme events?

Does climate change have a role in these extreme events that have occurred recently?

Scientific research has listed the extreme events most affected by human-caused climate change. At the top of the list are heat waves, followed by coastal flooding, drought, wildfires, reduced spring snowpack, very heavy rainfall, hurricanes and tropical storms, freezing weather, severe thunderstorms, hail, and tornadoes.

Are these extreme events telling us that climate change is happening faster than expected?

According to an article in Grist, climate scientists examined thousands of years of climate simulations to find unprecedented events. They discovered that this summer’s record-shattering heat is caused by burning coal, oil, and gas.

They find that the extreme heat this year would not likely have happened a generation ago, will likely occur more often in the next few decades, and is associated with increases in GHG emissions. It will only decrease when fossil fuel emissions fall.

Is climate change happening fast?

Michael Wehner, an extreme weather researcher at Lawrence Berkeley National Laboratory, described his reaction to the Pacific Northwest heatwave in June as “astonished”.

Researchers expected this type of event to happen later this century.  Wehner is a climate researcher who believes this heatwave would not occur without anthropogenic climate change.

When asked whether climate change is happening faster than expected, Daniel Swain, a climate scientist at the University of California, Los Angeles, answered negatively. Talking to the Grist, he says that “we’ve underestimated the impacts on some of the changes that were fairly well predicted.”

In a Q&A with Grist, Swain was asked whether these extreme events align with climate scientists’ predictions.

He says that climate scientists have long been predicting that extreme events will happen due to climate change, and the magnitude of these events has surprised some of them. Still, overall, these events are not entirely scientifically surprising. He added:

“Although the 1 to 1.3 degree of warming might not seem a lot to planetary scientists and those who study extreme events, this represents an enormous shift in the mean state of things. This shift in temperature could bring significant changes to other places like the Arctic, tropics, island nations, or the middle of a big continent.”

Did climate models fail to capture the extreme events?

According to Swain, global climate models tend to do very well at simulating global climate but sometimes fail to capture regionally-specific events like the heatwaves in Oregon and British Columbia “because the underlying physical processes are evolving on temporal and spatial scales that are finer than these models are intended to represent”.

Swain added that although global climate models fail to predict these regional and localized events, the weather models used daily to predict the weather did an excellent job of forecasting a week in advance the scorching temperatures that would hit Seattle, Portland, and British Columbia, as well as the extreme flood events before they hit Western Europe.

Swain said that for most people, except those who understand the dynamics of these nonlinear Earth system interactions, the one or two degrees increase in temperatures might not seem much, but this represents a tremendous shift in the system.

This lack of imagination of what could happen, and the magnitude of extreme events coming from this tiny shift in the system, can take most of us, and even scientists, by surprise, “and we’re adding a lot of extra energy to the system,” he said.

PHOTO CREDIT:

NASA Earth Observatory image of temperature anomalies on 27th June 2021 by NASA Earth Observatory/Joshua Stevens – https://earthobservatory.nasa.gov/images/148506/exceptional-heat-hits-pacific-northwest, Public Domain, https://commons.wikimedia.org/w/index.php?curid=107121230

Flood and damage in Tilff, Belgium on 16 July by Régine Fabri – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=107637907

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