2025 Nears Climate Heat Record, Mpox Variant Discovered, and Hobbit Extinction Explained
Kendra Pierre-Louis: For Scientific AmericanIt is Science quicklyMy name is Kendra Pierre-Louis, I’m replacing Rachel Feltman. You are listening to our weekly summary of scientific news.
First, the European Union’s Copernicus Climate Change Service reported last Monday that 2025 is shaping up to be the second hottest year on record, with data suggesting it will tie with 2023 for second. To learn more about what that means, we chat with Andrea Thompson, senior life sciences editor here at Scientific American.
Hi, Andrea.
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Andrea Thompson: Hi, Kendra.
Pierre-Louis: Thank you for joining us today. So yes, can you tell me more about what the European climate agency found?
Thompson: Yes, the agency looked at the global average temperature through the end of November of the year and found that we are about 1.48 degrees Celsius above the pre-industrial temperature, or roughly the last half of the 19th century. And that currently puts us tied for second place for 2023 in terms of ranking in the hottest years on record. The record holder is of course last year, 2024, which was the first year to exceed 1.5 degrees Celsius.
Pierre-Louis: And why is this 1.5 degree Celsius figure important?
Thompson: So that’s the number that the parish climate agreement, which was negotiated in 2015, 10 years ago, sort of set as an aspirational target. The overall objective was therefore to keep the rise in temperatures below 2 degrees Celsius…
Pierre-Louis: Mm-hmm.
Thompson: Above pre-industrial, but aim for a temperature below 1.5 degrees Celsius. So it was the first year where we exceeded this level.
This does not mean that we have completely violated the Paris agreement…
Pierre-Louis: RIGHT.
Thompson: Because this extends over an average of several years; it’s only been a year.
Pierre-Louis: And why does this number – zooming in a little more generally – mean, why does it matter that the Earth is warming so much? Should we be worried?
Thompson: We should definitely be worried. We can already see the effects of climate change on the weather.
Pierre-Louis: Mm-hmm.
Thompson: We are experiencing climate disasters. This is probably more easily noticeable during heat waves: we experience them more frequently. They are warmer. They last longer than before. But it manifests itself in many different climate extremes, in terms of floods, droughts, wildfires, and the fingerprints of climate change are becoming clearer and clearer in all of these types of disasters.
And of course, this has many other impacts as well. This affects agriculture. It affects ecosystems in ways that come back to humans and everything from, you know, fishing — whether a fishery is collapsing because the fish have moved away to more climate-friendly waters — to whether our infrastructure can cope with the climate that it’s sort of facing today when it was built for a climate that no longer exists.
Pierre-Louis: When they made this announcement, was there anything in particular that they noticed or something that they wanted to, like, point out that the average person should be aware of?
Thompson: Yeah, so I mean, there’s a few other things. The 10 warmest years on record all occurred primarily in the last decade, and almost all of the warmest years are in this century. So this shows how much of a difference climate change has made to the global average temperature, but also to what we all experience every day. We’ll probably have a three-year average above 1.5°C, which sort of brings us closer to the point where we’re going to violate the Paris climate agreement.
I think a lot of agencies always note this when they release these temperature records, that whether we continue to break these records and by how much depends entirely on the path we choose. So the more we get greenhouse gas emissions under control, primarily by stopping burning fossil fuels, you know, the less likely we are to continue to break these records in greater and greater quantities.
Pierre-Louis: Thank you very much for taking the time to speak with us today.
Thompson: Thank you for inviting me.
Pierre-Louis: Separately, the British Health Security Agency said it had detected a new strain of mpox in a person who had recently traveled abroad. The virus is spread through close physical contact with an infected person and has two types, or clades. Clade I is endemic to central Africa and has historically been more lethal. Clade II, generally less severe, is endemic to West Africa. Clades are further divided into smaller subtypes: clade IA and IB and clade IIA and IIB. Clade IIB is the cause of the current global outbreak that began in 2022 and has led to nearly 170,000 cases of mpox through October this year, according to data from the World Health Organization. The WHO reports that there have been nearly 48,000 confirmed cases of mpox worldwide so far in 2025.
The new strain identified in England contains elements of clade IIB and clade IB. The latter has recently shown signs of local transmission in parts of Europe and the United States, according to British health authorities. Researchers do not yet know what impact the new strain could have on transmission. The BBC also reported that it is unclear how effective protection the existing vaccine will be. The vaccine is currently about 75 to 80 percent effective in preventing mpox infection.
Speaking of public health, a study published last Monday in the Journal of the American Medical Association found that between 2017 and 2024, the proportion of newborns who did not receive a vitamin K injection increased by almost 80%. The number of newborns who have not been vaccinated has increased from around 3 percent to more than 5 percent.
Vitamin K is necessary for blood clotting, but newborns naturally have low levels of this nutrient. Skipping the injection means that up to one in 60 babies are at risk of developing bleeding due to vitamin K deficiency. This can lead to permanent brain damage or even death, according to SciAmreports on the research. Since the 1960s, the American Academy of Pediatrics has recommended that babies receive a vitamin K injection at birth to reduce this risk. The injection was considered a neonatal success.
Research on vitamin K refusal conducted by Jaspreet Loyal, a physician at Yale New Haven Children’s Hospital who was not involved in the study, provided insight into why some parents may refuse the injection. She said SciAm her research found that these parents may be under the mistaken impression that the risks outweigh the benefits or that they want to take a more “natural” route to child-rearing. Some online influencers have suggested giving babies vitamin K orally instead of the injection, but the oral version is not as easily absorbed and the injection carries negligible risks.
And now let’s move on to a hobbit mystery. At the center of the story is an early human parent called Homo floresiensis. The species’ small size has led scientists to nickname them hobbits, in homage to the fictional beings we all know and love. They even lived in their own version of a hobbit hole, settling for around 140,000 years in a cave called Liang Bua on an island in Indonesia. But around 50,000 years ago they simply disappeared.
Research published last Monday in the journal Nature Communications Earth and Environment could finally shed light on why. Scientists have reconstructed past climatic and rainfall conditions using the cave’s stalagmites. This led researchers to conclude that at the time Homo floresiensis disappeared, a severe drought set in, leading to a decrease in summer precipitation and seasonal drying of river beds. The researchers also analyzed the fossilized teeth of pygmy elephants, which were an important food source for hobbits. They discovered that these creatures depended on river water to survive. As the climate became drier, the number of pygmy elephants declined and the hobbits were left with less food. No second breakfasts, no elevenses, no lunches or afternoon teas. Scientists concluded that dwindling resources likely forced the hobbits to abandon Liang Bua.
What happened after the hobbits left the cave is still shrouded in mystery. But Mike Gagan, lead author of the study and honorary professor at the University of Wollongong in Australia, said in a statement: “It is possible that as they moved in search of water and prey, hobbits encountered modern humans. In this sense, climate change may have set the stage for their ultimate disappearance.”
That’s all for today’s episode. Tune in Wednesday, when we chat with SciAm Senior multimedia editor Kelso Harper, who spent the summer tracking orcas in the Pacific Northwest.
Science quickly is produced by me, Kendra Pierre-Louis, with Fonda Mwangi and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck check in on our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more recent and in-depth scientific news.
For Scientific American, This is Kendra Pierre-Louis. Have a good week!
