Enlarge / Wildfire smoke hovers over the Pacific coast of northern New South Wales, Australia in September 2019. (credit: Orbital Horizon/Copernicus Sentinel Data/Gallo Images via Getty Images)

The aerosol fallout from wildfires that burned across more than 70,000 square miles of Australia in 2019 and 2020 was so persistent and widespread that it brightened a vast area of clouds above the subtropical Pacific Ocean.

Beneath those clouds, the ocean surface and the atmosphere cooled, shifting a key tropical rainfall belt northward and nudging the Equatorial Pacific toward an unexpected and long-lasting cool phase of the La Niña-El Niño cycle, according to research published today in Science Advances.

Aerosols from wildfires are basically fire dust—microscopic bits of charred mineral or organic matter that can ride super-heated wildfire clouds up to the stratosphere and spread across hemispheres with varied climatic effects, depending on where they’re produced and where they end up.

Enlarge / Fire-damaged trees in a boreal forest near the Saskatchewan River in Alberta, Canada. As northern forests burn, they're releasing massive amounts of carbon. (credit: Ed Jones/Getty Images)

The far north is both a massive carbon sink and a potent environmental time bomb . The region stores a huge amount of CO ₂ in boreal forests and underlying soils. Organic peat soil , for instance, covers just 3 percent of the Earth’s land area (there’s some in tropical regions, too), yet it contains a third of its terrestrial carbon. And Arctic permafrost has locked away thousands of years’ worth of plant matter, preventing rot that would release clouds of planet-heating carbon dioxide and methane .

But in a pair of recent papers, scientists have found that wildfires and human meddling are reducing northern ecosystems’ ability to sequester carbon, threatening to turn them into carbon sources . That will in turn accelerate climate change, which is already warming the Arctic four and a half times faster than the rest of the world, triggering the release of still more carbon—a gnarly feedback loop.

Enlarge / Wolf Point Creek is likely the most-well-studied glacier-fed stream in the world. (credit: Elizabeth via Flickr (CC BY-NC 2.0) )

Pushing off from the dock on a boat called the Capelin , Sandy Milner’s small team of scientists heads north, navigating through patchy fog past a behemoth cruise ship. As the Capelin slows to motor through humpback whale feeding grounds, distant plumes of their exhalations rise from the surface on this calm July morning. Dozens of sea otters dot the water. Lolling on backs, some with babes in arms, they turn their heads curiously as the boat speeds by. Seabirds and seals speckle floating icebergs in this calm stretch of Alaska’s Glacier Bay.

Some two hours later, the craft reaches a rocky beach where Wolf Point Creek meets the sea. The creek is a relatively new feature on the landscape: Land at its mouth first became ice-free in the 1940s due to the melting and retreat of a glacier. It took shape through the 1970s, fed by a mountain lake that slowly formed as an isolated chunk of glacier ice slowly melted. Wolf Point Creek is special because almost its entire life span — from the first, sparse trickles melting out under the ice edge to a mature stream ecosystem teeming with aquatic life, from tiny midge larvae to small fish, and with willows and alder weaving along its edges — is known in intimate detail, its history painstakingly documented.

Milner, a stream ecologist at the University of Birmingham in the UK, has returned almost annually to this spot since the 1970s to catalog how life — particularly aquatic invertebrates — has arrived, thrived and changed over time. He was here to observe meager midges in 1977 and to spot a hundred prospecting pink salmon in 1989. A decade later, his team cataloged 10,000 of the fish spawning in Wolf Point Creek.

Enlarge (credit: Jeremy Moeller/Getty Images )

As soon as Lars Ruiter steps out of his car, he is confronted by a Microsoft security guard, who is already seething with anger. Ruiter, a local councillor, has parked in the rain outside a half-finished Microsoft data center that rises out of the flat North Holland farmland. He wants to see the construction site. The guard, who recognizes Ruiter from a previous visit when he brought a TV crew here, says that’s not allowed. Within minutes, the argument has escalated, and the guard has his hand around Ruiter’s throat.

The security guard lets go of Ruiter within a few seconds, and the councillor escapes with a red mark across his neck. Back in his car, Ruiter insists he’s fine. But his hands shake when he tries to change gears. He says the altercation—which he will later report to the police—shows the fog of secrecy that surrounds the Netherlands’ expanding data center business.

Enlarge / Westlands Solar Park, near the town of Lemoore in the San Joaquin Valley of California, is the largest solar power plant in the United States and could become one of the largest in the world. (credit: Carolyn Cole/Los Angeles Times via Getty)

California’s San Joaquin Valley, a strip of land between the Diablo Range and the Sierra Nevada, accounts for a significant portion of the state’s crop production and agricultural revenues. But with the state facing uncertain and uneven water supply due to climate change, some local governments and clean energy advocates hope solar energy installations could provide economic reliability where agriculture falters due to possible water shortages.

In the next two decades, the Valley could accommodate the majority of the state’s estimated buildout of solar energy under a state plan forecasting transmission needs [PDF], adding enough capacity to power 10 million homes as California strives to reach 100 percent clean electricity by 2045. The influx of solar development would come at a time when the historically agriculture-rich valley is coping with new restrictions on groundwater pumping. Growers may need to fallow land. And some clean energy boosters see solar as an ideal alternative land use.

But a significant technological hurdle stands in the way: California needs to plan and build more long-distance power lines to carry all the electricity produced there to different parts of the state, and development can take nearly a decade. Transmission has become a significant tension point for clean energy developers across the US, as the number of project proposals balloons and lines to connect to the grid grow ever longer.

Enlarge (credit: Walter Zerla via Getty Images)

Say you are a maker of computer graphics cards, under pressure from investors questioning your green credentials. You know what to do. You email your various departments, asking them to tally up their carbon emissions and the energy they consume. Simple enough. You write a report pledging a more sustainable future, in which your trucks are electrified and solar panels adorn your offices.

Good start, your investors say. But what about the mines that produced the tantalum or palladium in your transistors? Or the silicon wafers that arrived via a lengthy supply chain? And what of when your product is shipped to customers, who install it in a laptop or run it 24/7 inside a data center to train an AI model like GPT-4 (or 5) ? Eventually it will be discarded as trash or recycled. Chase down every ton of carbon and the emissions a company creates are many times times higher than it first seemed.

Enlarge / If this road is your only route to the outside world, it might not matter that your house didn't flood. (credit: Maurice Alcorn / EyeEm )

Climate change produces lots of risks that are difficult to predict. While it will make some events—heatwaves, droughts, extreme storms, etc.—more probable, all of those events depend heavily on year-to-year variation in the weather. So, while the odds may go up, it's impossible to know when one of these events will strike a given location.

In contrast, sea level rise seems far simpler. While there's still uncertainty about just how quickly ocean levels will rise, other aspects seem pretty predictable. Given a predicted rate of sea level rise, it's easy to tell when a site will start ending up underwater. And that sort of analysis has been done for various regions.

But having a property above water won't be much good if flooding nearby means you can't get to a hospital or grocery store when you need to or lose access to electricity or other services. It's entirely possible for rising seas to leave a property high, dry, but uninhabitable as rising seas cut connections to essential services. A group of researchers has analyzed the risk of isolation driven by sea level rise, and shows it's a major contributor to the future risks the US faces.

Enlarge / Magnified view of Vibrio vulnificus bacteria. (credit: Smith Collection/Gado via Getty Images )

Cases of a potentially fatal infection from a seawater-borne pathogen have increased off the US Atlantic coast as ocean waters warmed over the last 30 years and are expected to rise further in future because of climate change, according to a study published on Thursday by Scientific Reports, an open-access journal for research on the natural sciences and other topics.

The incidence of infections from Vibrio vulnificus , a pathogen that thrives in shallow, brackish water, was eight times greater in the Eastern US in 2018 than it was in 1988, and its range shifted northward to areas where waters were previously too cold to support it, according to the paper, “Climate Warming and Increasing Vibrio Vulnificus Infections in North America,” by academic researchers in the US, England, and Spain.

By the middle of the 21 ^st century, the pathogen is expected to become more common in major population centers, including New York City, and by the end of the century, infections may be present in every US Atlantic coast state if carbon emissions follow a medium- to high-level trajectory, the report said.