Climate Explained: Are We Doomed If We Don’t Curb Carbon Emissions by 2030?
By Robert McLachlan
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Is humanity doomed? If in 2030 we have not reduced emissions in a way that means we stay under say 2℃ (I've frankly given up on 1.5℃), are we doomed then?
Humanity is not doomed, not now or even in a worst-case scenario in 2030. But avoiding doom — either the end or widespread collapse of civilization — is setting a pretty low bar. We can aim much higher than that without shying away from reality.
It's right to focus on global warming of 1.5℃ and 2℃ in the first instance. The many manifestations of climate change — including heat waves, droughts, water stress, more intense storms, wildfires, mass extinction and warming oceans — all get progressively worse as the temperature rises.
Climate scientist Michael Mann uses the metaphor of walking into an increasingly dense minefield.
As I have been pointing out for some time, climate change isn't a cliff we go off at 1.5C or 2C. It's much more lik… https://t.co/tY8NoRq153— Michael E. Mann (@Michael E. Mann)1545928869.0
Good Reasons Not to Give Up Just Yet
The Intergovernmental Panel on Climate Change described the effects of a 1.5℃ increase in average temperatures in a special report last year. They are also nicely summarized in an article about why global temperatures matter, produced by NASA.
The global average temperature is currently about 1.2℃ higher than what it was at the time of the Industrial Revolution, some 250 years ago. We are already witnessing localized impacts, including the widespread coral bleaching on Australia's Great Barrier Reef.
This graph shows different emission pathways and when the world is expected to reach global average temperatures of 1.5℃ or 2℃ above pre-industrial levels. Global Carbon Project, Author provided
Limiting warming to 1.5℃ requires cutting global emissions by 7.6% each year this decade. This does sound difficult, but there are reasons for optimism.
First, it's possible technically and economically. For example, the use of wind and solar power has grown exponentially in the past decade, and their prices have plummeted to the point where they are now among the cheapest sources of electricity. Some areas, including energy storage and industrial processes such as steel and cement manufacture, still need further research and a drop in price (or higher carbon prices).
Second, it's possible politically. Partly in response to the Paris Agreement, a growing number of countries have adopted stronger targets. Twenty countries and regions (including New Zealand and the European Union) are now targeting net zero emissions by 2050 or earlier.
A recent example of striking progress comes from Ireland – a country with a similar emissions profile to New Zealand. The incoming coalition's "program for government" includes emission cuts of 7% per year and a reduction by half by 2030.
Third, it's possible socially. Since 2019, we have seen the massive growth of the School Strike 4 Climate movement and an increase in fossil fuel divestment. Several media organizations, including The Conversation, have made a commitment to evidence-based coverage of climate change and calls for a Green New Deal are coming from a range of political parties, especially in the U.S. and Europe.
There is also a growing understanding that to ensure a safe future we need to consume less overall. If these trends continue, then I believe we can still stay below 1.5℃.
The Pessimist Perspective
Now suppose we don't manage that. It's 2030 and emissions have only fallen a little bit. We're staring at 2℃ in the second half of the century.
At 2℃ of warming, we could expect to lose more than 90% of our coral reefs. Insects and plants would be at higher risk of extinction, and the number of dangerously hot days would increase rapidly.
The challenges would be exacerbated and we would have new issues to consider. First, under the "shifting baseline" phenomenon — essentially a failure to notice slow change and to value what is already lost — people might discount the damage already done. Continuously worsening conditions might become the new normal.
Second, climate impacts such as mass migration could lead to a rise of nationalism and make international cooperation harder. And third, we could begin to pass unpredictable "tipping points" in the Earth system. For example, warming of more than 2°C could set off widespread melting in Antarctica, which in turn would contribute to sea level rise.
But true doom-mongers tend to assume a worst-case scenario on virtually every area of uncertainty. It is important to remember that such scenarios are not very likely.
While bad, this 2030 scenario doesn't add up to doom — and it certainly doesn't change the need to move away from fossil fuels to low-carbon options.
Robert McLachlan is a Professor in Applied Mathematics, Massey University.
Disclosure statement: Robert McLachlan does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Reposted with permission from The Conversation.
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The ghoulishly named ogre-faced spider can "hear" with its legs and use that ability to catch insects flying behind it, the study published in Current Biology Thursday concluded.
"Spiders are sensitive to airborne sound," Cornell professor emeritus Dr. Charles Walcott, who was not involved with the study, told the Cornell Chronicle. "That's the big message really."
The net-casting, ogre-faced spider (Deinopis spinosa) has a unique hunting strategy, as study coauthor Cornell University postdoctoral researcher Jay Stafstrom explained in a video.
They hunt only at night using a special kind of web: an A-shaped frame made from non-sticky silk that supports a fuzzy rectangle that they hold with their front forelegs and use to trap prey.
They do this in two ways. In a maneuver called a "forward strike," they pounce down on prey moving beneath them on the ground. This is enabled by their large eyes — the biggest of any spider. These eyes give them 2,000 times the night vision that we have, Science explained.
But the spiders can also perform a move called the "backward strike," Stafstrom explained, in which they reach their legs behind them and catch insects flying through the air.
"So here comes a flying bug and somehow the spider gets information on the sound direction and its distance. The spiders time the 200-millisecond leap if the fly is within its capture zone – much like an over-the-shoulder catch. The spider gets its prey. They're accurate," coauthor Ronald Hoy, the D & D Joslovitz Merksamer Professor in the Department of Neurobiology and Behavior in the College of Arts and Sciences, told the Cornell Chronicle.
What the researchers wanted to understand was how the spiders could tell what was moving behind them when they have no ears.
It isn't a question of peripheral vision. In a 2016 study, the same team blindfolded the spiders and sent them out to hunt, Science explained. This prevented the spiders from making their forward strikes, but they were still able to catch prey using the backwards strike. The researchers thought the spiders were "hearing" their prey with the sensors on the tips of their legs. All spiders have these sensors, but scientists had previously thought they were only able to detect vibrations through surfaces, not sounds in the air.
To test how well the ogre-faced spiders could actually hear, the researchers conducted a two-part experiment.
First, they inserted electrodes into removed spider legs and into the brains of intact spiders. They put the spiders and the legs into a vibration-proof booth and played sounds from two meters (approximately 6.5 feet) away. The spiders and the legs responded to sounds from 100 hertz to 10,000 hertz.
Next, they played the five sounds that had triggered the biggest response to 25 spiders in the wild and 51 spiders in the lab. More than half the spiders did the "backward strike" move when they heard sounds that have a lower frequency similar to insect wing beats. When the higher frequency sounds were played, the spiders did not move. This suggests the higher frequencies may mimic the sounds of predators like birds.
University of Cincinnati spider behavioral ecologist George Uetz told Science that the results were a "surprise" that indicated science has much to learn about spiders as a whole. Because all spiders have these receptors on their legs, it is possible that all spiders can hear. This theory was first put forward by Walcott 60 years ago, but was dismissed at the time, according to the Cornell Chronicle. But studies of other spiders have turned up further evidence since. A 2016 study found that a kind of jumping spider can pick up sonic vibrations in the air.
"We don't know diddly about spiders," Uetz told Science. "They are much more complex than people ever thought they were."
Learning more provides scientists with an opportunity to study their sensory abilities in order to improve technology like bio-sensors, directional microphones and visual processing algorithms, Stafstrom told CNN.
"The point is any understudied, underappreciated group has fascinating lives, even a yucky spider, and we can learn something from it," he told CNN.
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