Punctual time travel depends on how fast the Earth spins

Can sea level changes help explain variations over the last 3,000 years?

(credit: Adrien Hebert)

Want to set your time machine to catch a solar eclipse with a group of curious Mesopotamians in the year 700 BCE? It's not as simple as you think. You need to adjust for the subtle slowing of Earth’s rotation over time and know the history of sea level change—and even those bits of knowledge might not be able to get you there on time. That's the conclusion that a team led by Harvard’s Carling Hay reached when it looked at what the ancient astronomical record tells us about our planet's timekeeping.

Tidal forces caused by the gravitational pull of the Sun and Moon act like a brake on the spinning Earth, gradually increasing the length of the day. It takes a long time for this to add up to anything meaningful, but the Earth has been around a long time: 400 million years ago, each year contained 400 days. At the current rate, days are growing just a couple milliseconds longer per century, so it would take more than 3.5 million years to add a minute.

This is not the answer to your plea for more time in the day to tackle your workload.

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Martian ice caps tell story of massive climate shifts

Layers record 4 million years of Martian climate history.

Enlarge / Mars' northern ice cap. (credit: ESA/DLR/FU-Berlin)

Earth has a climatic pacemaker driven by subtle patterns in its orbit. The shape of its orbit shifts slightly, the tilt of its axis bobs up and down, and that axis wobbles like a top. Add up the way all that movement affects the distribution of sunlight in the high latitude Northern Hemisphere, and you get a predictable succession of glacial and interglacial periods.

Mars has orbital patterns that affect its climate, too. In fact, Mars’ orbital cycles swing to greater extremes than Earth’s. For example, Mars’ current axial tilt is about 25°, but it has varied within a range of 18° to 48° over the past 10 million years. Those orbital changes have influenced its climate as well.

On Earth, the “ice ages” resulted in a transfer of water from the ocean into growing continental ice sheets. On Mars, the changes cause transfers of water ice from the polar caps to lower latitudes, where it forms thin layers and possibly even glaciers. When conditions tilt back the other way, ice disappears from lower latitudes and the polar caps thicken again.

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1.5 billion-year-old fossils reveal organisms of unusual size

Possibly related to algae, these simple critters grew as long as 30 centimeters.

Just a couple of 1.56 billion-year-old fossils from southern China. (credit: Maoyan Zhu)

The Cambrian “explosion” of life around 540 million years ago is one heck of a story, in which a huge variety of animal body plans first appear in the fossil record. But the harder we look, the more interesting and incredible the Cambrian prequels become. Now, there's a report of organisms big enough to be easily visible yet dating back to more than 1.5 billion years ago.

The fuse to the Cambrian bomb was quite long and, at the very least, had some firecrackers tied to it. Single-celled eukaryotes, organisms with a nucleus and other complex internal structures, joined the bacteria and archaea around 1.5 billion years before the Cambrian. About 60 million years before the start of the Cambrian, a considerable batch of complex organisms appeared, although their relationships to Cambrian life are contentious.

The history of multi-cellular eukaryotes in between is hard to piece together, as extraordinary luck is needed to preserve evidence of their soft cell bodies for us to find. We have a couple examples of tiny multi-cellular organisms that may have been eukaryotes, but a new discovery from a team led by Shixing Zhu of the China Geological survey adds a big one to the family. The long, flat fossils they found in 1.56 billion-year-old rocks were up to a whopping 30 centimeters long and 8 centimeters wide.

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Trump-owned golf course cites sea level rise in seawall permit

Despite candidate’s rejection of climate change, project acknowledges reality.

(credit: Gage Skidmore)

Republican presidential candidate Donald Trump hasn’t had to answer many questions about his position on climate change yet. But in a handful of colorful tweets over the last few years, Trump has made it clear that he rejects the conclusions of climate science, opting for descriptors like “hoax” and “bullshit.”

However, that belief is apparently not always reflected in the management of coastal property owned by Trump. A story in Politico reports that the permit request to build a seawall along a golf course and resort in Ireland, which Trump purchased in 2014, cites sea level rise as part of the reason for its construction. Coastal erosion is eating away at the property, and Trump is seeking to armor the beach with rock.

The environmental impact statement prepared for the prospective project explains, “If the predictions of an increase in sea level rise as a result of global warming prove correct, however, it is likely that there will be a corresponding increase in coastal erosion rates not just in Doughmore Bay but around much of the coastline of Ireland.”

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House Science Committee claims free speech attacks in Exxon probes

Republicans demand docs from attorneys general and environmental groups.

Rep. Lamar Smith, right (R-Texas) conferring with Rep. John Conyers (D-Mich.). (credit: Getty Images | Alex Wong)

Congressman Lamar Smith (R-Texas), who chairs the House Committee on Science, Space, and Technology, has used his subpoena powers liberally to seek the e-mails of climate scientists in the National Oceanic and Atmospheric Administration. Even before getting the evidence he claims he needs, however, Smith has accused NOAA of scientific dishonesty.

Rep. Smith and the 12 other Republicans on the committee have now turned their sights on a new target—actually, on 25 new targets. On Wednesday, letters were sent to 17 state attorneys general and eight environmental groups demanding e-mails and documents related to recent efforts to investigate Exxon Mobil’s past campaigns to downplay climate change.

Stories by Inside Climate News and the Los Angeles Times described climate research by Exxon scientists in the 1970s and 1980s. At the time, Exxon’s own scientists apparently made it clear to leadership that climate change was a threat. Building on those revelations, momentum has been building behind the accusation that Exxon intentionally mislead its shareholders (and the public) about climate change, both via its own company statements and through the funding of contrarian think tanks. Several attorneys general are now pursuing investigations of consumer and securities fraud akin to the investigations that damaged the tobacco industry in the 1990s—it's too early to know if these accusations have similar merits.

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Teenagers force Massachusetts to act on greenhouse gases via lawsuit

Supreme Judicial Court finds regulations were required by 2008 law.

The Massachusetts Supreme Judicial Court prepares to hear oral arguments in the case on January 8.

Some teenagers successfully lobby for access to the family car on a Friday night. Others successfully sue governments about not doing enough about greenhouse gas emissions.

Aided by the Conservation Law Foundation and the Mass Energy Consumers Alliance, four teens won a case before the Massachusetts Supreme Judicial Court Tuesday that will force the state to follow through on its greenhouse gas emissions goals. The state’s 2008 Global Warming Solutions Act pledged to reduce emissions to 25 percent below 1990 levels by 2020, but the Department of Environmental Protection (DEP) never created any emissions regulations to make that happen.

The lawsuit argued that the 2008 legislation required the DEP to actually do something, while the state said it interpreted the law to mean it would merely need to define numbers that would be consistent with the goal. The Supreme Judicial Court overturned a lower court’s decision, telling the DEP that it is not free to interpret the law that way.

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Model of Earth’s interior explains why Hawaii isn’t someplace else

Rather than blaming it on the tectonic plate, look about 2,000 kilometers below.

(credit: Google Earth)

The linear chains of islands running across the Pacific Ocean aren’t improbable coincidences of orderliness—they’re the product of hot towers of mantle rock punching volcanic holes through a tectonic plate sliding overhead. But if you follow the Hawaiian chain back to where the older seamounts no longer rise above the waves, you find a sharp dogleg, as you can see above.

We haven't had a satisfactory explanation for this sudden turn. One idea was that, given a stationary mantle hotspot, the tectonic plate must have changed direction at one point in time. This theory has never been entirely satisfactory, however—not least because the Louisville seamount chain in the South Pacific sports a gentler kink.

We still have a lot to figure out about how mantle hotspot plumes work, but we do know that the Hawaii and Louisville plumes go all the way down to the deepest part of the Earth’s mantle. Plumes like these are rooted near the edges of unusual, lumpy regions of rock at the base of the mantle beneath the Pacific (as well as Africa). These structures are known as large low-shear-velocity provinces—for lack of any reasonable alternative, we’ll grit our teeth and refer to them as LLSVPs.

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Current El Niño’s strength due partly to an earlier fizzle

The Pacific saved up for an El Niño in 2014 but held off on spending.

El Niño and La Niña may have diminutive names, but anyone who keeps an eye on climate news or weather reports knows their impact around the globe isn’t small. Like a mythical two-faced beast, the El Niño Southern Oscillation (ENSO) seems to have a mind of its own. Currently, we can’t forecast which one we’re going to get much more than a few months before it appears. So it’s interesting to look back and ask why an expected El Niño fizzled in 2014. It turns out the answer also helps explain why the current El Niño grew into such a monster.

The El Niño Southern Oscillation relates to the pattern of sea surface temperatures along the equatorial Pacific Ocean. In neutral conditions, the westward-blowing trade winds push surface waters aside, uncovering deeper, colder water along the South American coastline that wells up to the surface. Warmer surface water piles up on the other side of the Pacific, near the Philippines.

In a La Niña, more cold water is brought up in the east and the cool area spreads to the west. Conversely, an El Niño occurs when the warm water from the west sloshes eastward, putting a lid on the upwelling of cold water near South America. The different sizes and positions of these warm and cool patches of ocean water shift weather patterns around the globe, and help drive the global average surface temperature.

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Climate Hustle wants you to believe you just can’t trust climate science

If you missed the film’s one-night-only showing, you didn’t miss much.

(credit: CFACT)

Duane Gish, a prominent critic of evolution, was such a prolific debater that, like Dr. Henry Heimlich, he had a maneuver named after him. (The use of either maneuver at a party, incidentally, signifies that things have become decidedly un-fun.) While arguing, Gish would issue a rapid-fire stream of claims—most of them false—about so many different topics, that it would be impossible for his opponent to respond to them all. This quantity-over-quality tactic became known as a “Gish Gallop.”

On Monday night I took in a new film called Climate Hustle. The title is meant to reflect its central premise: climate change is a scientific con. But I soon realized that it was also a decent synonym for the film’s Gish Gallop style. Climate hustle (n): a fast-paced, uninterrupted delivery of superficial and false claims about climate science.

Do the hustle

Climate Hustle is the product of Marc Morano and the conservative Committee for a Constructive Tomorrow (CFACT). Morano, who has worked for Rush Limbaugh and Sen. James Inhofe (R-Okla.), now runs a climate “skeptic” blog supported by CFACT and makes regular appearances on cable news shows. His shift into movies is, so far, rather limited; the film appeared in a number of theaters in the US (and one in Canada) for one night only. The audience for this singular event numbered about 15 at my (admittedly quiet) local theater.

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When pests bite, a nightshade plant bleeds ant food

By producing nectar at wound sites, it calls for security detail.

Enlarge (credit: Tobias Lortzing)

Nature is, it’s often said, red in tooth and claw. But sometimes a claw scratches someone’s back in return for a symbiotic scratch of one’s own. Ants provide many examples of such mutually beneficial arrangements. As weird as it sounds, drinking the “blood” of a wounded bittersweet nightshade plant appears to be one of them.

Ants and plants are often good friends (leafcutters aside) because ants prey on insects that munch on the plants. Some plants keep ants on retainer by secreting nectar from special structures (fittingly called “nectaries”) that can be found in various parts of the plant. The acacia tree even goes as far as growing hollow thorns that ants can nest inside when they aren’t dining on the gourmet ant food the tree provides. (Full disclosure: acacias also drug the ants so they can’t live off other food sources. It’s a complicated relationship...) The benefits the tree obtains from its ant security detail apparently outweigh the energetic costs of these lavish gifts.

Something a little more subtle is going on with the bittersweet nightshade plant. A group of researchers led by Tobias Lortzing of the Free University of Berlin noticed that this nightshade bleeds sugary droplets when damaged, rather than quickly closing up its wounds. Seeing ants hit up those droplets for a snack, they wondered whether the plant adapted to call in ant support when herbivores come a-munching.

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