This was an important year for climate science, with humankind reaching exploring new depths, scaling new heights, and modeling new mechanisms. Some of the top discoveries in the field involved members of the Program of Atmospheres, Oceans and Climate (PAOC). Though not at all exhaustive, below is a list of some of the stories involving PAOC that significantly contributed to furthering the science of climate.
This year, a team of planetary scientists from Harvard and MIT, including PAOC member Sara Seager, used wine science to suss out the role sulfur dioxide played in brewing up Earth’s earliest life.
Volcanic eruptions, which spew massive amounts of sulfur dioxide into the atmosphere and water, have long been hypothesized to be an integral player in Earth’s origin-of-life story. However, no one knew to what extent, since the levels of sulfites and bisulfites present in natural waters at the time the first organisms appeared on Earth were unknown.
Enter: wine chemistry. Interestingly enough, apart from the bombardment of asteroids, early Earth conditions are actually mimicked during winemaking — a science that involves dissolving sulfur dioxide in water to produce sulfites and bisulfites under oxygen-less conditions.
Researchers turned to the robust literature on wine chemistry to see how the makeup of gases on early Earth would have dissolved in water, specifically, shallow water — the most conducive environment for life-forming reactions. The results showed that, nearly 4 billion years ago, large concentrations of sulfites and bisulfites from volcanos would have settled and dissolved in shallow lakes, potentially setting the stage for Earth’s first biological molecules.
Read why one scientist said this research “fundamentally changes our knowledge of early Earth” here.
For over 200,000 years, humans and their gut microbiomes have coevolved to create one of the most complex records of living organisms on the planet.
Now, a collaboration, called the Global Microbiome Conservancy, founded by postdocs in Summons Lab, has begun to preserve that record by collecting fecal samples from 19 distinct populations worldwide, from Arctic regions, Sub-Saharan countries, and North America. The hope is that these samples will better paint the picture of early climate by studying lifestyle indicators, such as lipids and molecules like cholesterol, in these microbiomes.
Already the team has come up with novel results, for instance, evidence of recent horizontal gene transfers and how an industrialized lifestyle diminishes gut bacterial diversity. The team is up against the clock, however, racing to collect their samples before the proliferation of antibiotic use erode gut bacterial diversity.
Click here to read more about this time-sensitive effort.
Like an oven giving off more heat to a surrounding kitchen as its temperature rises, the Earth sheds more heat into space as its surface warms up.
But, unlike the predictability of a kitchen, the Earth’s system is incredibly messy, with many complicated, interacting processes. For example, the water vapor feedback: As both the atmosphere and Earth heat up, say, by the addition of carbon dioxide, the air holds more water vapor, which in turn traps more heat in the atmosphere.
This Fall, however, a team led by postdoc Daniel Koll and Tim Cronin observed that water vapor absorbs infrared radiation (or heat) at incredibly specific wavelengths, allowing some to escape through, like opening a window in the kitchen. As things get hotter, however, the metaphorical window gets smaller: The increase in heat emitted by the atmosphere is cancelled out by the increased absorption from water vapor. Therefore, emission of heat from Earth’s surface to space is a simple function of surface temperature.
There’s a catch, however. The researchers also found the global average surface temperature at which this linear relationship breaks down. Read what that temperature is here.
In the Artic Ocean, just north of Alaska and Canada, an enormous, 600-mile-wide pool of swirling frigid, freshwater, called the Beaufort Gyre, holds the amount of freshwater equal to all of the Great Lakes combined. If unleashed, that reservoir has the power to dramatically disrupt worldwide ocean circulation.
Luckily, however, nature sometimes has a natural governor. This year, the Marshall Group identified the mechanism, called the “ice-ocean governor,” that keeps the gyre’s water safely contained — spinning but not spilling. In the Spring, as Artic ice melts, the gyre is exposed to winds that stir up the water and cause it to spin. In the winter, the ice acts as a lid, causing the water to bump against it and slow back down. In essence, the Artic ice is setting the speed limit for this major ocean current.
Changes to this natural balance—for instance, the continued climb of global mean temperatures and recession of Artic Ice—could have catastrophic consequences. Read what happens if the hypothetical levee breaks here.
Sometimes simple rules can carry over into messy reality. At least that’s what the Rothman group discovered in 2012, when they found that rivers split at a common 72-degree angle. The discovery was the first-ever formula for the near-ubiquitous, vein-like branching pattern of rivers, which Leonardo da Vinci once referred to as the “blood of the Earth.”
This year, the group added to that mathematical recipe with evidence that the shape of river networks—whether it is long and thin or short and squat—boils down to climate, specifically, the local availability of groundwater.
By combining mathematical principles with geological data, the team found that in dry regions of the U.S., river basins take on a long and thin contour, regardless of their size. But in humid environments, where the majority of rainfall seeps into the Earth, basins are heavily shaped by the local groundwater, which bleeds back up to carve out shorter, wider basins. The results, published in the Proceedings of the Royal Society A in July, may help scientists infer the kind of climate that was present when river networks—here on Earth or beyond—were initially incised.
Read the full story, including why the team had to slosh through streams in Florida to find their answers, here.
This was a big year for Mars. Within weeks of each other, reports came out that NASA’s Curiosity rover found evidence of complex organic matter on the Martian surface and then that a body of liquid water was found underneath its southern polar ice cap—both rewriting the odds of finding life on the Red Planet.
Fittingly, this past October, Mars expert John Grtzinger delivered the 8th annual John Carlson Lecture, in which he detailed the history of humankind’s search for life on the red plant—from early observations from afar to present-day rovers sifting through Martian soil in search of microbial life.
To a packed auditorium at the New England Aquarium, Grtzinger, a former MIT EAPS professor (now at Caltech), who served as project scientist of the Mars Science Laboratory mission, detailed how these modern-day trips to Mars have hunted for evidence of whether Mars’ climate and atmosphere was ever conducive to the survival of living organisms. The best evidence that it was? Topographic features suggesting the presence of ancient river channels, deltas, and maybe even an ocean on Mars… just like on Earth.
“This tells us that, at least, for some brief period of time if you want to be conservative, or maybe a long period of time, water was there [and] the atmosphere was denser,” said Grotzinger. “This is a good thing for life.”
Watch the whole talk below!
One of the biggest science news stories of the year was led by PAOC member Sara Seager.
This year, a massive NASA effort led by MIT scientists put a refrigerator-sized satellite in space, where it will spend two years collecting data on thousands of nearby exoplanets in order to answer a universal question: Are we alone?
Seager, who serves as the deputy director of science for The Transiting Exoplanet Survey Satellite (TESS), is heading the effort that sifts through photos from each of the satellite’s four cameras to determine the mass of passing by planets, including at least 50 Earth-sized ones. And mass, more so than size, can reveal a lot about a planet’s potential habitability, says Seager.
“If you just know that a planet is twice the size of Earth, it could be a lot of things: a rocky world with a thin atmosphere, or what we call a ‘mini-Neptune’ — a rocky world with a giant gas envelope, where it would be a huge greenhouse blanket, and there would be no life on the surface,” she said.
How do they do it? Read here to see how Seager and her team deploy a battery of methods to determine the mass of a potential planet.
Half-centennial anniversaries are traditionally marked by gifts of gold, which is fitting because this year marked the 50th anniversary of the MIT-WHOI Joint Program — the world’s golden standard of graduate degree program in marine science.
In toast to this golden anniversary, alumnae, scientists, and students came together at Woods Hole this September for a lively two-day celebration, full of fun and storytelling. One story in particular stood out: how the memorandum of agreement between MIT and WHOI was signed aboard the research vessel Chain, on May 8, 1968, thus launching the unorthodox academic experiment.
Since then, the program has boasted over 1,000 alumni, many of whom have gone on to become leaders in groundbreaking integrated research across the ocean sciences: physical oceanography, chemical oceanography, marine geology and geophysics, biological oceanography, and applied ocean sciences and engineering.
“We in the Navy think of this [program] as just a jewel, a bright star in the constellation of possibilities in ocean sciences,” said Admiral John Richardson, Chief of Naval Operations for the U.S. Navy, who earned three master’s degrees from the Joint Program in 1989. “MIT, WHOI, and the Navy have a rich history … of teaming together to tackle some of the toughest challenges that face our nation.”
Read more about the origins of this unorthodox partnership and this year’s celebrations here.
There are perhaps only a handful of scientists in the history of the world as well-respected and honored as MIT professors Jule Charney and Edward Lorenz. Born 100 years ago, the two pioneers of meteorology gave us numerical weather prediction and chaos theory, highlighting the value of basic research and forever changing the way we understand the weather and climate.
To mark the centennial of the scientists’ birth, this February, PAOC and The Lorenz Center organized a two-day symposium, MIT on Chaos and Climate, that brought together the MIT community and friends as well as welcomed back alumni, former faculty, and scientists from EAPS and the former Department of Meteorology (Course XIX).
The event honored more than just the scientific legacies of the two trailblazers. Former students and faculty shared fond memories of the men. Professor Charney was remembered as a man who brought people together through a combination of wisdom, optimism, and charm: “A tiger, a very friendly tiger.” Meanwhile, Lorenz was remembered as a quiet, humble soul: “A genius with a soul of an artist.”
Like the honorees’ research and mentorship, the event had a long-lasting impact. Alumni were so moved that funds to restore the Charney Library were raised. As a result, this December, the renovated library re-opened its doors to amazed and grateful students and faculty.
See photos and videos of the symposium here.
1. Climate modeling is being revolutionized.
One of the biggest announcements to come out of PAOC also happens to be one of the most recent.
On December 10, 2018, MIT announced that Professors Raffaele Ferrari and John Marshall will head the atmosphere and ocean side of a new nationwide consortium aiming to revolutionize climate modeling by using data assimilation and machine learning.
The new model, dubbed the Climate Modeling Alliance (CliMA), will be built in collaboration with researchers led by Caltech; the Naval Postgraduate School; and NASA’s Jet Propulsion Laboratory. To take advantage of new computer architectures, languages, and machine learning techniques, Ferrari and Marshall will also partner Alan Edelman's group in CSAIL at MIT, who will help code the new generation climate model in the computing language the group itself developed.
Read more about how the result will develop common hydro-dynamical cores, parameterizations, and machine-learning techniques for both atmosphere and ocean here.