Last week, Bill Gates published a 17-page memo on his personal website that critics said pitted climate and public health efforts against each other, when they should instead be working in tandem.

Monday night, speaking at Caltech in Pasadena, Gates doubled down, brushing off the critiques that came from across the ideological spectrum, including from climate scientists and President Trump.

Stressing that philanthropic resources are finite, Gates said he’s shifted some of his efforts from preventing climate change to reducing human disease and malnutrition in a world that he said will undoubtedly become warmer.

The United Nations’ 2025 Emissions Gap Report, published on Tuesday, says it’s likely that by 2100, global temperatures will have increased between 2.0 and 2.4 degrees Celsius compared to pre-industrial levels. Gates said he believes that number will be closer to 3 degrees Celsius.

“The real measure there is all the things we’re doing to help the most vulnerable people on the planet,” he said. He went on to say that he wants to refocus on scientific innovation that will remove climate-change-related costs — what he called a “green premium” — from technology to address hunger and sickness in the poorest countries in the world.

Climate scientists raised concerns about Gates’ memo released last week, arguing it inaccurately isolated the challenges of disease and hunger from climate change. “They are not separate problems, they are problems being exacerbated by this very issue,” said Katharine Hayhoe, a leading atmospheric scientist who studies climate change, in a forum Tuesday afternoon with other scientists.

At Caltech, in front of over 1,000 people — a mix of mostly students and professors — Gates expressed frustration with climate scientists who critiqued his memo as erroneously downplaying the potential impacts of climate change.

“What world do they live in?” he asked at one point, arguing that his critics were not taking into account that you could do more to save lives by spending money to address disease and other issues than by investing in reducing carbon emissions.

“It’s a numeric game in a world with very finite resources,” Gates said on Monday night. “More finite than they should be.”

Gates also rebuked Trump, who he said made a “gigantic misreading” of the memo in a Truth Social post last Wednesday that suggested Gates was no longer a climate change believer.

“I’m a climate activist, but I’m also a child survival activist, and I hope you will be too,” Gates told the crowd at Caltech. “That’s the best way to make sure that everyone gets a chance to live a healthy life, no matter where they’re born or what climate they’re born into.”

The billionaire said that his shift in focus to human health is intended to support poor countries that typically receive aid from the U.S. and other rich nations, at a time when the U.S. has backed away from such largesse. The Trump administration in July paused most foreign aid payments, which make up just about 1% of the national budget, but which researchers at the nonprofit Center for Global Development have found save some 3.3 million lives worldwide.

At Caltech, Gates also discussed technologies he supports to mitigate climate change, including nuclear fusion reactors and geo-engineering.

Gates’ critics within the climate science world say he is focusing on the wrong things. “He’s sort of perpetually downplayed the importance of the clean energy transition with the technology we have in favor of promoting some future tech,” said Michael E. Mann, a climate scientist at the University of Pennsylvania. It could take decades for some of those technologies to be implemented at scale, said Mann. “We don’t have decades to address the climate crisis.”

It’s been two years since a Santa Cruz sea otter, known as 841, garnered international attention and celebrity by attacking surfers and their surfboards as the human wave-riders alley-ooped over the waves of the legendary Steamer Lane.

It’s happening again.

This time, the identity of the otter is unclear. That’s because while 841 (who was born in captivity) carried a light blue tag on her right flipper, this otter is naked.

Experts say 841 could have chewed off her tag, or it could have broken off on its own. Otter flipper tags are designed to last an animal’s lifespan, but research shows they don’t always last so long.

It’s also possible this is an entirely different otter who may have watched 841 in the past, and is adopting her curious and bold behavior. It could be a relative. Or it could be this otter just has a similar surfboard appetite and hostage-taking drive.

On Thursday afternoon, roughly three dozen surfers were lined up to catch waves at Steamer Lane — just below the Santa Cruz coastline’s cliffs near the city’s iconic lighthouse and surfer statue.

Mark Woodward, a Santa Cruz-based social media influencer and dedicated 841 observer and chronicler, said he wasn’t sure whether this was 841, or someone different.

He said the animal’s behaviors and M.O. were almost identical. However, while 841 tended to hang close to the cliffs in 2023, this otter appeared to spend more time a bit farther out — closer to the offshore kelp beds.

He saw 841 last year — tag on — visiting the same waters but keeping her distance from people.

The only otter seen on Thursday was way off shore, floating on its back atop a kelp bed — presumably eating some tasty morsel, such as a crab or abalone, retrieved from the sea floor.

Pelicans glided over the cresting waves, while a harbor seal watched the surfers for a bit before diving under the surface and disappearing from sight.

During the summer of 2023, federal wildlife officials tried to capture 841. They sent out boats, rafts and swimmers. She evaded every attempt and eventually gave birth to a pup, whom she cradled on her chest as she floated atop the water — or placed on top of the kelp as she dived to the bottom to retrieve food. And she stopped chasing surfboards.

Eric Laughlin, spokesman for the California Department of Fish and Wildlife, said the U.S. Fish and Wildlife Service is the lead otter-response agency in this case. However, possibly due to the federal government shutdown, the agency did not respond to questions about the surfing-curious otter in Santa Cruz.

Laughlin said the state agency had no plans “to intervene with the sea otter currently interacting with humans in Santa Cruz.”

Research on California sea otters shows that along the central coast, there is “extreme individuality in diet and behavior.” Some of the variation is the result of relatively low food availability, requiring the clever creatures to figure out unique ways of finding and retrieving food.

However, the researchers also noted some behavioral traits seemed to follow family lines, especially those “maintained along matrilines.”

Surfers at Steamer Lane in Santa Cruz on July 13, 2023.

(Gary Coronado / Los Angeles Times)

Advertisement

Otter 841 was born in captivity to a mother who had been captured after spending too much time interacting with people and their watercraft. Since being released into the wild, she has given birth to at least two pups.

According to Woodward, the otter now frequenting Steamer Lane has been actively pursuing surfers nearly every day since Oct. 16, when it bit a surfer named Bella Orduna and stole her board.

Dripping wet and donned in a wet suit, Richard Walston, 55, said he hadn’t had any interactions with the surfer-curious creature — and he’s a frequent surfer in the area.

“Sure, I see otters,” he said. “But they’re so focused on their food, I’m not sure they even notice we’re around.”

Wildlife officials are urging surfers and boaters to keep their distance from this otter, and others — not only will this reduce the chances of an interaction, which could be dangerous for both people and otters, it is the law.

Late last month, California fire officials made a courtesy call to Los Angeles.

The state’s proposed Zone Zero regulations that would force homeowners to create an ember-resistant zone around their houses — initially planned to take effect nearly three years ago — had caused an uproar in the region. It was time for damage control.

Officials from both Cal Fire and the state’s Board of Forestry and Fire Protection visited Brentwood, the epicenter of the outrage, and Altadena, where homeowners are trying to figure out how best to rebuild, but did little to assuage the concerns of the Zone Zero proposals’ most vocal critics.

The two groups took turns pointing out homes that seemed to support their claims. The copious, contradictory anecdotal evidence provided no consensus for a path forward. For example, in the Eaton burn area, officials showed residents a home they claimed was spared thanks to its removal of vegetation near the home, but residents noted a home across the street with plenty of plants that also survived.

It was an example of what’s become an interminable debate about what should be required of homeowners in L.A.’s fire-prone areas to limit the destruction of future conflagrations.

Initial attempts by the board to create Zone Zero regulations, as required by a 2020 law, quietly fizzled out after fire officials and experts struggled to agree on how to navigate a lack of authoritative evidence for what strategies actually help protect a home — and what was reasonable to ask of residents.

The Jan. 1, 2023, deadline to create the regulations came and went with little fanfare. A month after the January fires, however, Gov. Gavin Newsom signed an executive order resurrecting the efforts and ordering the board to finish the regulations by the end of the year. As the board attempted to restart and speed-run the previous efforts through a series of public meetings, many Californians grew alarmed. They felt the draft Zone Zero requirements — which would be the strictest statewide defensible space rules on the books — were a step too far.

“The science tells us it doesn’t make sense, but they’re ignoring it because they have to come up with something,” said Thelma Waxman, president of the Brentwood Homeowners Assn.,who is working to certify neighborhoods in her area as fire safe. “If I’m going to go to my members and say, ‘OK, you need to spend $5,000 doing one thing to protect your home,’ it’s not going to be to remove hydrated vegetation.”

Instead, she wishes the state would focus on home-hardening, which has much more compelling research to support its effectiveness.

Tony Andersen, the board’s executive officer, stressed that his team wants to keep requirements evidence-based and reasonable for homeowners. “We’re listening; we’re learning,” he said.

Zone Zero is one of the many fire safety regulations tied to the fire hazard severity maps created by Cal Fire, which, while imperfect, attempt to identify the areas in California likely to see intense wildfire.

Since 2008, all new homes in California in areas that those maps determined have very high fire hazard are required to have multi-paned or fire-resistant windows that are less likely to shatter in extreme heat, mesh coverings on all vents so flying embers can’t sneak inside and ignition-resistant roofing and siding.

The state’s defensible space regulations break down the areas surrounding a home into multiple zones. Zone Two is within 100 feet of the home; in that space, homeowners must remove dead vegetation, keep grass under 4 inches and ensure that there is at least 10 feet between trees. Zone One is within 30 feet of a structure; here, residents cannot store firewood. Zone Zero, within 5 feet, is supposed to be “ember-resistant” — essentially meaning that there cannot be anything that might ignite should embers land within it.

The problem is, it’s unclear how to best create an “ember-resistant” zone. For starters, there’s just not a lot of scientific evidence demonstrating which techniques effectively limit ignitions. That’s especially true for the most controversial Zone Zero proposal: removing healthy plants.

“We have very few publications looking at home losses and vegetation patterns in Zone Zero,” said Max Moritz, a wildfire-dynamics researcher with UC Santa Barbara and the UC Cooperative Extension program.

Further complicating the problem, the board also needs to consider what is reasonable to ask of homeowners. Critics of the current proposal point out that while wooden fences and outbuildings are banned, wooden decks and doors are still fine — not because they cannot burn, but because asking residents to replace them is too big of a financial burden and they are, arguably, out of the purview of “defensible space.” And while many in the L.A. area argue they should be allowed to keep plants if they’re well-watered, the board cannot single-handedly dictate water usage for ornamental vegetation across the state.

To deal with the head-spinning complexity, the state started with a small working group in 2021 that included Cal Fire staff, local fire departments and scientists. The working group slowly grew to include more local leaders and came close to finalizing the rules with the board as it neared the Legislature’s Jan. 1, 2023, deadline. But as the parties got stuck on the final details, the deadline came and went. Zone Zero slowly fell off the meeting schedules and agendas and for two years, essentially nothing was done.

Then, L.A. burned.

In February 2025, Newsom signed an executive order pushing the board to finish the regulations by Dec. 31. As the board began hosting public hearings on the regulations, shock and frustration had set in among Californians.

To add insult to injury, Newsom’s executive order also pushed Cal Fire to release new hazard maps that the Legislature had also mandated. When the agency did that in the spring, many Californians were distraught to learn that the maps added over 300,000 acres — mostly in developed areas — into the classifications where Zone Zero will apply.

At a (now somewhat infamous) Zone Zero meeting at the Pasadena Convention Center in September — the only one to take place in Southern California — public comments stretched on for over five hours. They included several speakers more accustomed to receiving public comments than making them: The mayor of Agoura Hills, representatives for L.A. City Council members and the chair of L.A.’s Community Forest Advisory Committee.

Alongside marathon public meetings, the board received more than 4,000 letters on the regulations.

In a September report to L.A.’s City Council, the Los Angeles Fire Department and the city’s forestry committee chastised the board for failing to consult the city during the process and only holding its Pasadena meeting “after persistent pressure from local advocates … six months into the rulemaking process.” It also pointed to a 2025 study that found many home-hardening techniques play a much more significant role in protecting homes than defensible space.

Most of the Zone Zero proposals have generally received agreement or at least acceptance among the public: No wooden mulch, no wooden fence that attaches to the house, no dead vegetation and only outbuildings made of noncombustible materials. But two issues quickly took center stage in the discourse: trees and plants.

Residents have become increasingly concerned with the prospect of cutting down their trees after the working group began discussing how to handle them. However, the current proposals would not require residents to remove trees.

“It’s pretty much settled,” Andersen said. Well-maintained trees will be allowed in Zone Zero; however, what a well-maintained tree looks like “still needs to be discussed.”

What to do about vegetation like shrubs, plants and grasses within the first 5 feet of homes has proved more vexing.

Some fire officials and experts argue residents should remove all vegetation in the zone, citing examples of homes burning after plants ignited. Others say the board should continue to allow well-watered vegetation in Zone Zero, pointing to counterexamples where plants seemed to block embers from reaching a home or the water stored within them seemed to reduce the intensity of a burn.

“A hydrated plant is absorbing radiant heat up until the point of ignition, and then it’s part of the progression of the fire,” said Moritz. The question is, throughout a wildly complex range of fire scenarios, when exactly is that point reached?

In October, the advisory committee crafting the regulations took a step back from its proposal to require the removal of all living vegetation in Zone Zero and signaled it would consider allowing well-maintained plants.

As the committee remains stuck in the weeds, it’s looking more and more likely that the board will miss its deadline (for the second time).

“It’s more important that we get this right rather than have a hard timeline,” Andersen said.