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Why climate change hits the world’s poor harder

Ethiopians carrying jerrycans of water.

You’re living in Sub-Saharan Africa during a drought entering its second year. The diminished harvests have left you without enough food, and your family is trying to figure out how to get by. You’ve settled on selling some of your livestock and securing a small loan to help cover the cost of food, confident that you’ll be able to recover quickly and repay your debt.

Some of your friends, however, have less wealth than you. If they sell their last two cattle, it could be a long time before they could afford to replace them. And given that their annual income is highly variable, they can’t risk taking out a loan they may not be able to pay back. So rather than dig themselves into a potentially inescapable hole, they eat less and go hungry. Some of those families have growing children, but they see no other way.

In situations like these, those in poverty can be significantly more vulnerable than their wealthier counterparts. When you have little, your flexibility to deal with unpredictable crises is limited.

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IPCC finally weighs in on how to avoid further climate change

If you were collecting sections of the new report from the Intergovernmental Panel on Climate Change, you can now complete your set. Following the release of the section on the physical science of climate change in September and the section on the impacts of, and adaptations to, climate change just two weeks ago, the section on how to avoid future warming was finally released over the weekend in Berlin.

This section was written by 235 scientists from 58 countries and cites almost 10,000 studies. The final publication of the entire report will take place in October, along with a short synthesis report summarizing the key findings in simpler, less-technical terms.

How we got here

If you add up all the human-caused greenhouse gas emissions around the world in 2010, it was equivalent to 49 billion tons of CO2. That number isn’t just growing, its growth is accelerating. Over the previous decade, it increased by about one billion tons each year, while the average from 1970-2000 was about 0.4 tons more each year. More than three-quarters of these emissions come from fossil fuels, and the rest come from things like deforestation, livestock production, and industrial pollutants.

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IPCC report says climate change is bad news for crops

When it comes to projections of future global warming, most people are more interested in concrete impacts than abstract figures like average global temperature. That sort of information is contained in the second section of the latest IPCC report, which was just recently released. Among the things potentially impacted by climate change, the agricultural sector is of obvious relevance to those of us who eat food. (That includes you, Soylent fans.)

Given that population growth and economic progress in developing countries is expected to raise the demand for food by about 14 percent each decade, will climate change make it harder for farmers to feed the world?

It’s a complicated question with a number of relevant factors to consider. Temperature is the most obvious one. Many crops have problems with temperatures much above 30 degrees Celsius (86 degrees Fahrenheit), meaning regions that are already hot may not have much wiggle room. Warming also changes the timing of the spring thaw (but not the seasonal changes in daylight) and expands the growing season in some places. Then there’s precipitation, both in terms of rainfall and the high-elevation snow that can feed rivers in the summer. Together with temperature, changes in precipitation can alter soil moisture, either directly or by affecting sources of irrigation water. Those changes can also mean shifts in the range or prevalence of pests and diseases that plague crops.

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Seismic imaging revisits an old question: What drives continental drift?

Iceland is a portion of a mid-ocean ridge, where the oceanic plates spread apart and new crust is made in between, that rises above sea level.

Long before geologists worked out the theory of plate tectonics, there was discussion about whether Earth’s continents had moved about. The most detailed, and most famous, case was made by Alfred Wegener after the turn of the 20th century. The best objection to his idea was that he couldn’t provide a plausible mechanism that could drive this “continental drift."

In a 1928 volume, Arthur Holmes proposed a possible answer: convection of rock in the mantle could drag the plates around. This ended up being the dominant explanation when plate tectonics was accepted. But there have since been some challengers. One alternative that could move plates is the density-driven downward sinking of oceanic plates at subduction zones, which people recognized would exert a force that pulled on the portion of the plate that was still at the surface—what’s known as “slab pull.” Once the plates are moving, they'd simply drag nearby mantle along with them.

Now, thanks to some finely detailed imaging, researchers have come up with evidence that, in at least one location, the mantle drove plate motion, rather than being swept up by it. The results will have to be confirmed at other plate boundaries, but it's a good start towards settling one of the oldest arguments in plate tectonics.

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New IPCC report on climate change focuses on managing risks

IPCC Chairman Rajendra Pachauri speaking at a press conference announcing the release of the new report.

A few months ago, we covered the release of the first section of the new Intergovernmental Panel on Climate Change (IPCC) report, which dealt with the physical science of climate and climate change. After one last meeting in Yokohama, Japan, the authors of the section on climate “Impacts, Adaptation, and Vulnerability” have released the final draft of their work. (One additional section will be released in just a couple of weeks, with a synthesis report and the full, official release due at the end of October.)

This thirty-chapter report on climate impacts is the product of 679 scientists from around the world, and it cites over 12,000 studies. Its goal is to summarize observed climate impacts, lay out future risks, and describe types of adaptation that could help manage those risks.

The Summary for Policymakers—the portion of the report subjected to line-by-line approval by government representatives—reads a little differently than past versions, in large part due to an emphasis on risk management as the overarching framework used to consider climate impacts. Its scope is also a little broader than simply earth sciences, as it discusses things like the potential for violent conflicts inflamed by the added stress of climate change.

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Asteroid-like body appears to have rings

Artist's conception of Chariklo's rings.
Lucie Maquet

Centaurs are one of the mythical creatures invented by combining two organisms you wouldn’t regard as similar—in this case, parking a human torso on a horse’s shoulders. A group of oddball objects in our Solar System in orbit beyond the asteroid belt have earned the name “Centaur” because they're a bit like asteroids and a bit like comets. Recent observations of one of them show that it lives up to the spirit of the name in another way as well. It’s sporting a rakish accessory you probably associate with planets—rings.

Each of the gas giants in our Solar System—Jupiter, Saturn, Neptune, and Uranus—has rings, though only Saturn’s are visually prominent. Rings, which are made of many small chunks of ice or rock, can form when a moon comes too close to its host. The difference in gravitational pull from one side of the moon to the other can actually rip it apart. Rings can also form from other sources of material, like collisions between moons, or even particles ejected by moons like Saturn’s ice-spewing Enceladus.

At about 250 kilometers wide, “Chariklo” is the largest of the Centaurs. It orbits the Sun at a distance between Saturn and Uranus, but astronomers think it may have been brought in from an orbit beyond Neptune less than ten million years ago.

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Cambrian hunter switched to a plankton diet

Artist's conception of Tamisiocaris borealis lunching, with one front appendage filtering plankton from the water and the other bringing the catch to its mouth.
Bob Nicholls/Bristol University

The fossilized organisms of the Cambrian period some 500 million years ago are both alien and familiar. A few of them look a lot like the creatures around us today. But even some that don’t look at all familiar hold down ecosystem roles we can easily recognize—photosynthesizers, grazers, predators.

The alien inhabitants of the ecosystem are well-represented by Anomalocaris and its kin. Looking like something out of a sci-fi movie, these arthropod-like animals were probably the kings and queens of the Cambrian seas—the top of the food chain. They grew up to a meter or two in length and swam around in search of prey to seize with the two appendages in front of their round, disc-like mouth.

At least some of them did, at least. New fossils suggest that at least one anomalocarid ended up exchanging its role as a top predator for a more sedate lifestyle.

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Mercury (the planet) shrinks as it cools

The curving ridge near the day/night divide in the center of this image is one example of the features created by Mercury's contraction.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

The theory of plate tectonics is only a few decades old, meaning that a great many geologists working prior to its discovery had much more trouble understanding the landscape around them than we do today. Some of the ideas that popped up to fill this vacuum can seem peculiar to us now.

Take, for example, the “contracting Earth” hypothesis championed in the 1800s by James Dwight Dana and also proposed by Élie de Beaumont. They sought to make sense of mountain ranges, faults, and bending folds of rock with an appeal to Earth’s thermal history. The Earth had likely cooled from an initial molten state, they reasoned, and should therefore also have contracted in size. The outer crust of the Earth, exposed as it is, would have cooled first. As the hotter interior continued cooling and shrinking, the already-solid crust would have to crinkle, crack, and buckle in response—hence the faults and mountain ranges.

While this turned out to be the wrong explanation for the geology on Earth, it was rescued from the bin of discarded hypotheses by other bodies in the Solar System.

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Dust in the wind helped bring down CO2 in the past

Atmospheric simulation of aerosol transport in December, 2006. Dust is shown in red.
William M. Putman and Arlindo M. da Silva, NASA/GISS

Over the past three million years, the Earth has experienced rhythmic swings in and out of glacial conditions paced by a drummer named Milankovitch. The Milankovitch cycles in Earth’s orbit around the Sun change the way the Sun’s light strikes the surface of our planet. But these climatic swings would have been much smaller if not for the amplifying effect of changing greenhouse gas concentrations. (Returning to a band metaphor, a rock concert would be pretty unremarkable if you disconnected the amps from the guitars.)

Climate records like ice cores very neatly show us how those concentrations changed over time since they hold bubbles of ancient air trapped in the ice. But it’s up to us to figure out why greenhouse gasses moved in to and out of the atmosphere. For example, where did all the atmospheric CO2 go when the warm interglacials descended back into glacial conditions?

Hiding carbon in the ocean

The Southern Ocean has been the prime suspect. There, CO2-rich deep ocean water rises to the surface and exchanges gas with the atmosphere. If that ventilation were too slow, atmospheric CO2 would fall. Reduced upwelling caused by a lid of lower-density water near the Antarctic coast, for example, could explain up to 40 parts per million of the approximately 100 parts per million decrease in CO2 over the recent glaciations.

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Out-of-body experiences are harder to remember

Fox Entertainment

If you think about it, memory is an astounding thing. At will, our brains can dig back through the archives and pull out the sights, sounds, smells, sensations, and emotions from a day long gone. All those memories have one pretty obvious thing in common—everything about an experience is recorded from a first-person perspective. But what happens if your memory is not in first-person.

Some people go through what is commonly referred to as “out-of-body experiences,” where they feel a sense of detachment from their body as if they were somehow floating above it. This and related "dissociative" phenomena can be a part of posttraumatic stress disorder or schizophrenia, for example. The people who have out-of-body experiences often seem to have difficulty recalling these experiences with the usual amount of detail. That could be a clue about how our memories work, but how could you design an experiment to test the possibilities?

Loretxu Bergouignan and Henrik Ehrsson of Sweden’s Karolinska Institute and Umeå University’s Lars Nyberg have an answer. They utilized a setup that simulates the feeling of an out-of-body experience by transporting a subject's perception of sight and sound across the room. (Science writer Ed Yong has first-hand knowledge of this non-first-person experience.) Subjects wear a virtual-reality-like display connected to stereo cameras and microphones that can be placed elsewhere. Under controlled conditions (holding still, etc.) the illusion can be quite profound.

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