From Cliff Mass’s Weather Blog
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Looks like there’s another harsh climate “tipping point” headlines every day.
The threats of catastrophic, irreversible climate change are just around the corner.
It is true that such claims by some media and climate activists is contrary to the best science.
A plot to sow anxiety and confusion, with the motive of motivating people to “do the right thing”. And it’s both unethical and counterproductive.
What is a climate tipping point?
According to the Merriam-Webster dictionary, the tipping point is defined as
critical point in a situation, process, or system beyond which a significant and often unstoppable impact or change occurs
And a climate tipping point can be defined asa critical threshold that, when crossed, results in large and often irreversible changes in the climate system.
Specifically, the idea is that increasing greenhouse gases (such as CO2) will lead to warming and produce large, irreversible changes in the climate system.
Like driving off a cliff. And the subsequent reduction of greenhouse gas emissions and concentrations won’t help. The changes will be irreversible. We cannot go back.
Sounds scary doesn’t it?
Fortunately, the best science shows that such tipping points do not threaten our planet’s global climate system.
Yes, global warming due to increased greenhouse gases is expected. But the result is that climate changes over the next century will be slow and reversible. There are no climate simulations due to the sharp increase in CO2 indicating a tipping point.
Consider the collection of 20 CMIP-5 global climate model simulations, running with CO2 emissions from extremely high (RCP8.5) to higher probable (RCP4.5). As shown below, there is some variation in the warming process for each of these warming scenarios, but there are NO instances where it suddenly becomes uncontrollably hot. There is no cut-off point. Other climate simulations suggest the same thing.
What about global warming in the Northwest?
As part of my research, I ran high resolution climate models driven by a very aggressive RCP8.5 scenario. Looking at dozens of regional simulations, each driven by a different international climate model, there is NO EXPAND POINT for Seattle temperatures over the next century. Just a steady increase with some variation around the mean.
What about IPCC (Intergovernmental Panel on Climate Change)the most famous and respected authority on global warming and climate change?
They emphasize that there is no evidence of imminent tipping points (in the next century) for Earth’s climate. Let me provide some examples.
Lost Arctic sea ice? Here’s what the IPCC (Special Report on the Effects of 1.5C or More Warming, Chapter 3) says:
“yes little evidence for a tipping point in the transition from perennial to seasonal ice. No evidence has been found for irreversible or tipping points, suggesting that year-round sea ice will return if the climate is right.”
Melting of Arctic permafrost releases warming methane? There is no tipping point
“the amount of carbon released into the atmosphere from melting permafrost is predicted to be limited to 0.09–0.19 Gt C year–1 at 2°C of global warming and 0.08 –0.16 Gt C year–1 at 1.5°C, which does not indicate a tipping point.”
Heatwaves and heatwave deaths? Here’s what the IPCC says
An increase in ambient temperature was linearly associated with hospitalization and death when specific thresholds were exceeded (hence, no cut-off point).
Global warming is a serious problem but there is no imminent cliffhanger for the global climate. There is no imminent tipping point for global climate.
In that case, some climate advocates got creative and are now pushing local tipping point. A recent paper (Lenton et al., 2019) claims ripe local tipping points (see below), including changes in fires and pests in Canada. Many of these claims are not supported by the best science.
Even the Seattle Times joined the tipping point crowd, claiming that climate change threatens the tipping point for the Western Red Cedar (see below). As I will discuss in a future blog, this Seattle Times article is full of errors.
Climate deception
Climate tipping points are doing the devil’s work. They know that the impacts of human-caused climate change are now relatively modest. But people are not motivated enough to take the actions the activists want. So they decided to scare people off, with a terrifying climate change impending.
Not ethical, not based on science. And they are damaging people psychologically and driving governments to make bad decisions.
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