Climate Is a 'Threat Multiplier' But Not Primary Cause of East African Conflict and Displacement, Study Finds
While there are predictions that climate change will displace masses of people in the near future—an Environmental Justice Foundation study reported on by The Guardian put the number in the tens of millions within the next decade—some have indicated that the climate refugee crisis has already begun.
But when a team of researchers at University College London (UCL) set out to track the relationship between climate, conflict, and displacement in East Africa over the past 50 years, they found that climate change had not been the main force behind wars and displacement.
Insead, the study, published in Palgrave Communications Tuesday, found that conflict and displacement were primarily driven by population, economic and political factors.
Focusing on 10 East African countries from the period from 1963 to 2014, researchers compared a database of incidents of political violence and the number of displaced people per country with global temperature records, the Palmer Drought Index, and data on population growth, population size, Gross Domestic Product and change in Gross Domestic Product, life expectancy and political stability.
A map of the 10 East African countries featured in the UCl study.Palgrave Communications
They found that population growth, slow economic growth and political instability were the leading causes of conflict and internal displacement.
However, when they looked specifically at refugees, that is, displaced people forced to cross borders, they found that severe drought did play a role in forcing their movements, along with population growth, economic stagnation and political strife.
"The question remains as to whether drought would have exacerbated the refugee situation in East Africa had there been slower expansion of population, positive economic growth and more stable political regimes in the region," lead author Erin Owain said in a UCL press release.
"Terms such as climate migrants and climate wars have increasingly been used to describe displacement and conflict, however these terms imply that climate change is the main cause. Our research suggests that socio-political factors are the primary cause while climate change is a threat multiplier,"UCL Professor Mark Maslin said in the press release.
This means that governments in East Africa have a crucial role to play in protecting their populations as the impacts of climate change increase. Africa is particularly vulnerable to climate change overall, and East Africa is projected to see increasingly intense and unpredictable rainfall, according to the study's introduction.
"Our research suggests that the fundamental cause of conflict and displacement of large numbers of people is the failure of political systems to support and protect their people," Maslin said.
The conclusions indicate that East African leaders can do a lot for their populations without having to wait on global action on climate change.
First Study on Climate Change and Internal Migration: World Bank Finds 140 Million Could Be Displaced by 2050… https://t.co/2QjLqLc8ZQ— EcoWatch (@EcoWatch)1521553458.0
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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In 'Road Map for a More Sustainable Future,' NY Regulator Tells Banks to Consider Climate Risks in Planning
By Brett Wilkins
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