Humans have a greater influence on the world's landscape than previously thought, according to a comprehensive new high-resolution analysis of human modification of the planet. The map, published in the journal Global Change Biology, is meant to guide conservation strategy in the coming years.

Why it matters: The new study finds that just 5% of the Earth’s land surface is currently unaffected by humans, far lower than a previous estimate of 19%.

• 95% of the Earth's land surface has some indication of human modification, while 84% has multiple human impacts, the study found.

“As a conservation community, we can’t just say once we’ve protected these last remaining wild places then we’re done, because the vast majority of the world is not those places."

How they did it: The researchers from The Nature Conservancy and Conservation Science Partners used publicly available, high-resolution data from ground surveys and remotely sensed imagery on land use in 1 square kilometer grids to provide a spatial assessment of the impact of 13 human-caused stressors across all terrestrial lands, biomes and ecological regions, including:

• Agriculture
• The physical extent of human settlement
• Transportation, including railroads and minor roads
• Mining, energy production
• Electrical infrastructure, including power lines

By the numbers:

• 52% of ecological regions and 49% of countries are considered moderately modified. These regions are highly fragmented, retain up to only 50% of low modified lands and fall within critical land use thresholds.
• Only 30% of terrestrial ecological regions and 18% of the world’s countries have a low degree of land modification and retain most of their natural lands, which are distant from human settlements, agriculture and other modified environments.

The study found the least modified biomes tend to be in high latitudes and include tundra, boreal forests, or taiga and temperate coniferous forests.

On the other hand, the most modified biomes include more tropical landscapes, such as temperate broadleaf and mixed forests, as well as mangroves.

What they're saying:

“Conservation organizations agree that the large intact landscapes remaining on the planet are conservation priorities. But our results suggest that less of the world’s land remains unaltered by human activities, and most are in a state of intermediate modification at the threshold of critical tipping points...”

Yes, but: Other conservation groups focus more on the remaining wild places and have especially ambitious goals. For example, famed biologist E.O. Wilson advocates setting aside 50% of the world as preserves, including marine areas, up from about 15% of the land that is currently protected.

He told Axios' Alison Snyder in 2017 that expanding such reserves is essential for saving species that would otherwise go extinct.

"Only one-fifth [of species] have been stopped in the slide down towards extinction. Four-fifths have been continuing in spite of all our efforts around the world," Wilson said then.

New, independent observations from ocean buoys and other data sources show Earth's oceans are warming at a rate that's about 40% faster than indicated in the 2013 UN Intergovernmental Panel on Climate Change report.

Why it matters: The study, published Thursday in the journal Science, resolves a key uncertainty in climate science by reconciling analyses from a variety of different scientific teams — and underscores the complex and potentially limited immediate impacts of cutting greenhouse gas emissions.

The impact: Warmer oceans are already causing unprecedented back-to-back coral bleaching events and are contributing to sea-level rise. They're also causing glaciers to melt from below in Greenland and Antarctica.

• Warmer waters provide critical fuel for extreme storms, with studies showing ties between Hurricane Harvey's devastating deluge and warmer than average waters in the Gulf of Mexico, for example.

Why you'll hear about this again: The oceans are the reason why climate change will not relent even if emissions were to cease today, since they will continue to release heat, and also greenhouse gases, over time.

There are also implications for carbon removal technologies, which are getting more attention from scientists and investments from major oil companies. Lost in much of the discussion on carbon removal, however, is the potential for the oceans to spoil the party.

“The climate system has a long memory. ... It doesn’t warm as quickly as it otherwise would, and it’s a lot harder to cool it back down once it starts warming.”

The bottom line: "Just like the oceans buffer the rate of warming, they would also similarly buffer the rate of cooling in a world where we had net-negative emissions," Hausfather says.

• He cited a 2016 study that showed it would take slightly more negative emissions to reduce warming than it takes positive emissions to increase temperatures.

Go deeper: Ocean heat is climbing 40% faster than thought

Researchers have developed a phone app they say could reduce the number of opioid overdose deaths by using sonar to detect symptoms and urgently message family, friends or emergency responders, Eileen Drage O'Reilly writes.

Why it matters: Opioid overdoses kill an average of 130 Americans per day, but the immediate administration of naloxone and supportive respiratory care can dramatically reduce the death rate, the researchers tell Axios. The app is the subject of a study published Wednesday in Science Translational Medicine.

Yes, but: Outside experts, meanwhile, say that while this may be a good step toward developing more tools, the technology is not advanced enough to target areas that would more significantly impact the epidemic.

Background: Most unintentional opioid deaths are caused by respiratory failure, which exhibits two main precursors — frequent cessation of breathing or breathing drops to 7 breaths/minute or lower. After the overdose, there is a 5–10 minute window to administer naloxone, a medication-assisted treatment that reverses the temporary breathing symptoms.

"By targeting these precursors, we hope to detect overdose early, to maximize the window between when someone is in trouble and summoning help."

What they did: The University of Washington research team developed the app, called Second Chance, and tested it in two locations: a supervised-injection facility in Vancouver and an operating room where they simulated overdose events.

How it works: The system works by transforming the phone into an active sonar, similar to a bat or submarine, study author Shyamnath Gollakota says.

• The phone's speaker transmits inaudible acoustic signals, which receive reflections off the human body to monitor breathing.
• If overdose symptoms are detected, it would notify naloxone-equipped friends, family or emergency medical services.

What they found: At the Vancouver facility, the app detected symptoms 90% of the time for up to 3 feet. At the operating room, it alerted 19 of the 20 simulated overdoses.

Limitations: The authors say most of the research was in monitored situations, so they are looking to repeat in a more natural location.

Go deeper: Opioids app aims to lower response times for overdose victims

Polar vortex split (podcast): Kim Hart guest hosts Axios' Pro Rata Podcast and discusses the implications of a triple split of the polar vortex for winter weather in the U.S. and Europe.

Trump threatens California: In a Tweet, President Donald Trump threatened to cut off FEMA funds for California wildfires due to the state's land management practices, Marisa Fernandez reports.

Cancer deaths disparity: There's good news and bad news in new cancer statistics, Eileen writes. In particular, troubling socioeconomic gaps in cancer death rates have emerged in the U.S. for certain types of cancer.

Carbon emissions spike: A new Rhodium Group analysis shows that U.S. carbon emissions from energy — which is the largest source of emissions — jumped by 3.4% last year, ending years of declines, Ben Geman reports.

Science shutdown: The government shutdown is affecting science in increasingly significant ways, from National Weather Service forecast offices to students waiting to hear about postdoc spots.

Fast radio bursts: Using a new observatory, scientists have detected more of the mysterious radio signals that seem to be emanating from high-energy sources in distant space, such as a black hole. Such Fast Repeating Radio Bursts have about 25 million times more energy than our sun, Loren Grush reports for The Verge.

Broken Hubble: The Hubble Space Telescope's wide field camera has gone offline, as non-furloughed workers try to fix the problem from the ground at mission control, Alan Boyle reports for GeekWire.

CRISPR scientist appears: He Jiankui, the controversial scientist who announced in November that he had implanted genetically edited embryos that led to the birth of twins, has emerged from some sort of house arrest in China, according to a scoop from Sharon Begley of Stat News.

Strange magnetic drift: Earth’s magnetic North Pole has been drifting toward Siberia, "driven by liquid iron sloshing within the planet’s core," writes Alexandra Witze for Nature News. She reports that, in a rare move, the World Magnetic Model, which is a foundation of modern navigation, will be updated to take this into account (once the government shutdown ends).

In about 10 billion years, our sun is likely to turn into a white dwarf — a shrunken, extremely dense star whose nuclear core has burned out and gotten rid of its outer layers.

A new study published Wednesday in the journal Nature claims to reveal the first evidence that white dwarf stars form solid, crystal cores containing metallic oxygen and carbon. The oldest white dwarfs, the study finds, are likely to be almost fully comprised of crystals.

Why it matters: The process of crystallization, similar to water turning into ice but occurring at far higher temperatures (about 10 million degrees Celsius), slows the cooling of these stars, potentially making them billions of years older than originally thought. Scientists use white dwarfs as markers of time in order to get a better idea of the age of surrounding stars and planets.

What they did: Astronomers from the University of Warwick in the U.K. used observations from the European Space Agency's Gaia satellite to examine the luminosities and colors from about 15,000 white dwarf candidates within about 300 light-years of Earth.

• They found a large number of stars that had colors and luminosities that seemed to match the phase in a star's development when it's releasing huge amounts of latent heat, which results in a slower cooling process.
• According to a press release, such stars may have slowed their aging by as many as 2 billion years.

"This means that billions of white dwarfs in our galaxy have already completed the process and are essentially crystal spheres in the sky."