from the world's big
Human-driven climate change meets 'gold standard' of scientific certainty
New statistical analyses show that human-driven climate change is a virtual certainty.
- While it's difficult to find people who deny climate change is happening, some still argue that humans are not climate change's primary cause.
- By applying peer-reviewed statistical methods to 40 years' worth of satellite data, researchers have determined that the evidence of human-driven climate change has passed the gold standard of scientific certainty: the five-sigma level.
- This threshold is used in particle physics to determine the existence of new particles; now, it's being used to definitively state that humans are the cause of climate change.
As if there were any reason to doubt the 97% of climate scientists who believe that climate change is driven by human activities, now more data has confirmed what we already knew. The fact that the five most recent years have been the five warmest in 139 years, the fact that global temperatures have risen by 0.8°C since 1880, and the fact that arctic sea ice is decreasing by 12.8% per decade are definitively attributable to human-driven climate change.
The new certainty comes from a recent article by Benjamin Santer of the Lawrence Livermore National Laboratory and colleagues. The article, published in Nature Climate Change, looked at three of the most relied-on satellite datasets used to conduct climate science: Specifically, the Remote Sensing Systems (RSS), the Center for Satellite Applications and Research (STAR), and the University of Alabama in Huntsville (UAH) datasets.
The researchers were looking through the datasets for a specific signal—that is, the "thumbprint" of human-induced climate change—in the noise of the data—the general variance in the climate. They found that the likelihood that the current change in climate is derived from human activities has surpassed the "gold standard" of statistical significance, or the five-sigma level.
For most, the fact that the researchers detected the fingerprint of human-driven climate change at the five-sigma level probably means exactly nothing. Sigma refers to a standard deviation—a measurement of how spread out a value is from the mean or average. Another way of thinking about it is that the sigma levels correspond to how likely it is that a given observation actually matches what one is looking for versus how likely it is that the observation has arisen from random chance.
Generally, the five-sigma level, or five standard deviations, is used in particle physics as the threshold before a discovery can be declared. Because many of the observations from particle physics can occur by chance rather than from, say, a newly discovered type of particle, physicists tend to set the bar high. When an observation meets the five-sigma level, it means that only once out of 3.5 million times could the observation have occurred by chance. This threshold was used to declare the discovery of the Higgs boson and the first detection of gravitational waves.
Now, lead author Santer claims that the three biggest datasets on climate change show that human-driven climate change has reached the five-sigma level: There is a one in 3.5 million chance that our climate is changing because of some other reason than human activities. "The narrative out there that scientists don't know the cause of climate change is wrong," said Santer in an interview with Reuters. "We do."
This graph depicts the signal-to-noise ratio found in the three datasets over time. The signal refers to human-driven climate change, while the noise refers to the general variance in our climate.
The RSS (red) and STAR (blue) datasets showed that the evidence for human-driven climate change has passed the five-sigma level a while ago, but the UAH (green) dataset only passed this threshold recently. (Santer et al., 2019)
Making use of 40 years of satellite data
Santer and colleagues' work was based on the previous work by Klaus Hasselmann, who developed a statistical approach for attributing climate change to various sources. Hasselmann's original work was developed in 1979, however, only a year after the first satellites began collecting data on global temperature. By modifying Hasselmann's approach and applying it to the 40 years of satellite data we now have access to, Santer and colleagues could track the growing likelihood of human-driven climate change.
Because of variations in satellite instrumentation, condition, and configuration, not all three datasets showed the same level of confidence in human-driven climate change. As Santer writes, "In two out of three datasets, fingerprint detection at a 5σ [five-sigma] threshold—the gold standard for discoveries in particle physics—occurs no later than 2005, only 27 years after the 1979 start of the satellite measurements." In 2016, the third dataset from the UAH satellite also showed that the fingerprint of human activity in climate change passed the five-sigma threshold. In the conclusion of his article, Santer summarized these findings as succinctly as possible: "Humanity cannot afford to ignore such clear signals."
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Construction of the $500 billion dollar tech city-state of the future is moving ahead.
- The futuristic megacity Neom is being built in Saudi Arabia.
- The city will be fully automated, leading in health, education and quality of life.
- It will feature an artificial moon, cloud seeding, robotic gladiators and flying taxis.
The Red Sea area where Neom will be built:
Saudi Arabia Plans Futuristic City, "Neom" (Full Promotional Video)<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="c646d528d230c1bf66c75422bc4ccf6f"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/N53DzL3_BHA?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
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Frequent shopping for single items adds to our carbon footprint.
- A new study shows e-commerce sites like Amazon leave larger greenhouse gas footprints than retail stores.
- Ordering online from retail stores has an even smaller footprint than going to the store yourself.
- Greening efforts by major e-commerce sites won't curb wasteful consumer habits. Consolidating online orders can make a difference.
A pile of recycled cardboard sits on the ground at Recology's Recycle Central on January 4, 2018 in San Francisco, California.
Photo by Justin Sullivan/Getty Images<p>A large part of the reason is speed. In a competitive market, pure players use the equation, <em>speed + convenience</em>, to drive adoption. This is especially relevant to the "last mile" GHG footprint: the distance between the distribution center and the consumer.</p><p>Interestingly, the smallest GHG footprint occurs when you order directly from a physical store—even smaller than going there yourself. Pure players, such as Amazon, are the greatest offenders. Variables like geographic location matter; the team looked at shopping in the UK, the US, China, and the Netherlands. </p><p>Sadegh Shahmohammadi, a PhD student at the Netherlands' Radboud University and corresponding author of the paper, <a href="https://www.cnn.com/2020/02/26/tech/greenhouse-gas-emissions-retail/index.html" target="_blank">says</a> the above "pattern holds true in countries where people mostly drive. It really depends on the country and consumer behavior there."</p><p>The researchers write that this year-and-a-half long study pushes back on previous research that claims online shopping to be better in terms of GHG footprints.</p><p style="margin-left: 20px;">"They have, however, compared the GHG emissions per shopping event and did not consider the link between the retail channels and the basket size, which leads to a different conclusion than that of the current study."</p><p>Online retail is where convenience trumps environment: people tend to order one item at a time when shopping on pure player sites, whereas they stock up on multiple items when visiting a store. Consumers will sometimes order a number of separate items over the course of a week rather than making one trip to purchase everything they need. </p><p>While greening efforts by online retailers are important, until a shift in consumer attitude changes, the current carbon footprint will be a hard obstacle to overcome. Amazon is trying to have it both ways—carbon-free and convenience addicted—and the math isn't adding up. If you need to order things, do it online, but try to consolidate your purchases as much as possible.</p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
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