091: Fourth National Climate Assessment, and more

On This Week’s Show

  • The science news of the week
  • The Climate Lounge with Tom Di Liberto
  • And the Pub Quiz

Science News with Dr. Amrita Sule and Sophie McManus

Cosmic Airburst May Have Wiped Out Part of the Middle East 3,700 Years Ago

We all have seen shooting stars at night. Millions such small asteroids are thought to orbit on paths that bring them near Earth. So, once in a while as noted in history a comet or a meteorite can come very very close to the earth surface and explode – causing massive destruction events called cosmic airbursts.

A team of researchers from Jordan’s Tall el-Hammam Excavation Project have found evidence that a cosmic airburst took place about 3,500 years ago. This explosion of a comet or a meteor destroyed around 500 square kilometers, wiping out all human life and a vast area of fertile land north of the Dead Sea called Middle Ghor.

This airburst left the fertile lands barren as they were deposited with anhydride salts from the Dead Sea due to a tsunami which was caused by the aftershocks from the airburst. It took almost 600 years for the area to recover before any civilization could be restored.  

How did the archeologists come across the evidence of this airburst? They found and studied 3,500 year old pieces of pottery from the Tall el-Hammam excavation site and discovered that it was vitrified, turned into glass. This would require extremely high temperatures around 4,000˚ C. Just for reference the temperature on sun is about 5,600˚ C.

This was so powerful that zircon contained in the pottery turned into glass. Radiocarbon dating at the site indicated that mud-brick walls “suddenly disappeared around 3,700 years ago, leaving only stone foundations.”

A similar air burst that took place in Tunguska, Siberia in 1908 had a blast radius of 2,000 square kilometers, suggesting that the explosion which destroyed the Middle Ghor region occurred at a low altitude, possibly not more than one kilometer above the ground.

The most recent airburst took place in February 2013 when a meteor exploded over Central Russia. This event injured about 1,500 people and damaged thousands of buildings.

These cosmic airbursts continue to be an impending threat to the planet. Scientists are working on developing warning and response systems to deal with such cosmic events.

Live Science

Fox, ‘Cosmos' Producers Investigate Sexual Misconduct Claims Against Host Neil deGrasse Tyson

Neil deGrasse Tyson

Neil deGrasse Tyson has been accused by three women of sexual misconduct and an investigation will take place shortly.

In one allegation, Katelyn Allers, an associate professor of astronomy and physics at Bucknell University in Pennsylvania, claimed Tyson inappropriately touched her in 2009 while admiring a space tattoo on her upper left arm. Another woman, Ashley Watson, claimed that she quit a position as Tyson's assistant due to inappropriate sexual advances. Those claims follow an earlier allegation by musician Tchiya Amet, who claimed Tyson raped her while both attended graduate school.

deGrasse Tyson has written a piece addressing the claims titled ‘On Being Accused’.

“I'm the accused, so why believe anything I say? Why believe me at all?” Tyson wrote. “That brings us back to the value of an independent investigation, which FOX/NatGeo (the networks on which Cosmos and StarTalk air) announced that they will conduct. I welcome this. … Accusations can damage a reputation and a marriage. Sometimes irreversibly. I see myself as loving husband and as a public servant – a scientist and educator who serves at the will of the public.  I am grateful for the support I’ve received from those who continue to respect and value me and my work.”

Trial, or rather manhunt, by social media is ridiculous, so it’s good that Fox and NatGeo are getting on with an investigation. I read both Degrasse Tyson’s account and one of the blogs detailing the assault, for this story. I have my own opinion, but given that I’ve just denounced trial by social media I think I’ll keep it to myself…!

New York Times, Space.com

As Natural As Spider’s Milk

The kingdom Animalia never ceases to surprise us. And one of the recent discoveries is about jumping spiders, Toxeus magnus. According to a study published in Science, Female Toxeus Magnus spiders secrete a milk like fluid to feed their offspring. But wait! Spiders are not mammals, and isn’t breastfeeding is fundamental to being mammals?

Apparently not. Over time scientists have discovered that animals such as flamingos, cockroaches and male emperor penguins produce nutrient rich milk-like substances to feed their young.

The discovery that Toxeus magnus spiders secrete a milk-like fluid was carried out by lead author Zhanqui Chen of the Chinese Academy of Sciences. Chen observed that young T. magnus spiders were slow to leave their breeding nests – suggestive of extended childcare. Chen's team noticed in the lab that the newborns and the mother remained in the next for about 20 days. A closer they revealed that during first week the mother deposited droplets of white fluid from her underside on to the nest, which the newborns would drink. After that the newborns directly drank from the underside of the mother.

The mother continued to provide milk for 20 more even when the young spiders would leave their nests to forage. These young spiderlings returned to the nest for mother’s milk until finally weaning at 40 days of age.

When Chen blocked the opening (same when they lay eggs) from which the fluid was secreted, the hatchlings did not survive beyond 11 days which shows their complete dependence on this fluid. Chen and colleagues found that this milk like white fluid was extremely rich in proteins. It contained four times as much protein as cow’s milk. The authors are okay with calling this fluid spider’s milk even though it does not come from a mammary gland. They are more interested in how it supports the offspring.

Chen and colleagues plan to study how does T. magnus generates this fluid. This discovery challenges the dogma that lactation is uniquely a mammalian trait. They don’t know yet if this is seen in any other spiders.

These rare variants in the animal kingdom will help in providing insights about evolution of lactation and parental care.

New York Times

Researcher who created CRISPR twins defends his work

Lots to think about here. Let’s refresh briefly on what exactly has happened.

A few days ago, a researcher in China claimed to have CRISPR-edited human embryos to prevent them from contracting HIV. He Jiankui of the Southern University of Science and Technology in nearby Shenzhen, China, said he was “proud” of the work, which he said could lead to disease prevention “for millions of children.”

While CRISPR technology has been used in a preliminary way in human material, what’s truly controversial about this work is the claim that the edited embryos were allowed to develop to term. That’s right – this work apparently resulted in the birth of two babies. The announcement he had done this was only made when the twin girls had been born.

Earlier this week, He announced in an Associated Press (AP) interview and a series of YouTube videos that his team had engineered the genomes of twin baby girls to cripple a key receptor, CCR5, that HIV uses to infect white blood cells—a modification they may pass onto their descendants. Mutations in the CCR5 gene confer HIV resistance, and He said previous experiments have suggested CCR5 was a promising target for editing. But He didn’t explain how gene editing could help the world prevent the disease; nobody thinks it’s feasible to edit the genomes of entire populations.

Several things to consider.

Did this work actually happen? Or is it a poorly judged attempt at some sort of fame/notoriety?
If the researcher indeed edit human embryos which were then born, what has this work done to them other than (possibly) mediating their risk of contracting HIV? A long-winded way of saying, what other stuff has he messed with?! CRISPR is known as an incredible tool to modify genetic information, but it is also known to cause many undesirable off-target effects.
Did the parents really understand what was being done? Apparently He claimed this work was part of a vaccine development project to some potential patients.

For any listeners unfamiliar with the furore surrounding the potential of CRISPR, this work represents a lot of controversy. This technique isn’t considered clinically safe. Nor have we reached any consensus on whether it is morally acceptable to tamper with the genome of human embryos. Particularly otherwise HEALTHY embryos. The phrase ‘playing God’ is likely to be bandied about.

The water is murkier still. Perhaps unsurprisingly, given the huge moral repercussions of gene editing human embryos, it appears this work was not funded or sanctioned by the scientist’s research institution. They are now investigating him! Another point worth making is – who’s going to publish this? Reputable journals would be likely to reject this work on ethical grounds alone. He says the work has been submitted to a peer reviewed journal, but many unanswered questions remain, for example which hospital he did the work at, why he hadn’t mentioned this work earlier (for example when the woman was pregnant), what success rate he found, what adverse effects may have arisen in failed attempts.

Back to the actual aim of this work, to make the girls resistant to contracting HIV. But, I mean, were they at risk of contracting HIV in the first place?  Why alter ostensibly healthy embryos while risking off-target genetic effects? Even if they are exposed to HIV, which they have been ‘edited’ to avoid, you know they COULD still get it. I mean some people are naturally immune to HIV, but they STILL can get it, if it gets through an alternative route!!! There are ways to avoid HIV that don’t involve gene editing! This isn’t an unmet medical need. There’s no way to prove that this work has benefitted the girls, as if they don’t catch HIV, that isn’t necessarily because of He’s work!

I’ll close with some comments made by Jennifer Doudna, one of the inventors of CRISPR as we know it today. Doudna is ‘horrified’ by this story, if it is true.

If you want to know more about the fallout, I recommend a great Atlantic article by Ed Yong titled The CRISPR Baby Scandal Gets Worse By The Day.


The Climate Lounge

United States National Climate Assessment and the start of COP24

Tom Di Liberto

It’s good to be back in The Lounge. A lot has happened since I last ranted….I promise I’m going to try and rant less and hope more. So instead of trying to cover every specific last thing that’s happened climate-related on this planet, I’m going to talk about a broad new report that was recently released by the US Government, the Fourth National Climate Assessment.

First a disclosure, everything I say is my own opinion and does not reflect upon my employer. Also, I work at one of the agencies that helped produce the report but I did not have a hand in making it. With that said, let’s get into it.

The Fourth National Climate Assessment was released on Friday, 23 November, better known as the day after Thanksgiving, which sigh…obviously was done to reduce the number of eyeballs paying attention. WHY would this have been done? Well, let me read verbatim what is under the “Communities” header in the summary findings

“The impacts of climate change are already being felt in communities across the country. More frequent and intense extreme weather and climate-related events, as well as changes in average climate conditions, are expected to continue to damage infrastructure, ecosystems, and social systems that provide essential benefits to communities. Future climate change is expected to further disrupt many areas of life, exacerbating existing challenges to prosperity posed by aging and deteriorating infrastructure, stressed ecosystems, and economic inequality. Impacts within and across regions will not be distributed equally. People who are already vulnerable, including lower-income and other marginalized communities, have lower capacity to prepare for and cope with extreme weather and climate-related events and are expected to experience greater impacts. Prioritizing adaptation actions for the most vulnerable populations would contribute to a more equitable future within and across communities. Global action to significantly cut greenhouse gas emissions can substantially reduce climate-related risks and increase opportunities for these populations in the longer term.”

This report is following the science and because of that is pulling no punches. You might be thinking how in the world was this released by the current US government? Well, the National Climate Assessment is a Congressionally mandated report that comes out roughly every 4 years by law. This report has been in the process of creation starting before the current administration took office and they had no right to stop it. Now, for our international listeners, this report does NOT go into the global impacts currently and in the future of climate change. Instead, it has a specific focus on how climate change is impacting and will continue to impact the United States (and all that entails). It looks at all scenarios for the future and explains what will happen to extreme weather impacts, climate change impacts on coastal, interior, mountains…you get the picture. In fact, it breaks down the US into regions and each region gets its own section to discuss impacts. It is a thorough and massive effort done by tons of scientists, a lot of whom did this in their free time not getting paid a scent. Now the reaction to this release has been predictable. With fabrications, deflections and did I mention fabrications? A lot of lies out there trying to downplay this report's conclusions….including insisting it wasn’t based on data. Uhmm, it’s basically all data! Each statement has a citation after it leading to a peer reviewed journal article. It’s a data nerd's dream!

Or that scientists were getting rich off of this. Which, HAHAHA, oh lord that’s a good one!

Or that it was only based off a worst case scenario. It wasn’t. But you get this picture.

Now they tried to bury this report so I think all Americans should do our part to keep talking about it. It also includes sections on what to do about the problem, and reducing risks which are great things to focus on. Solutions are good, people. Because climate change isn’t going away and it’s going to get worse.

Now before I leave, I’d be silly not to mention that the annual UN Conference on Climate Change or COP24 is taking place currently in Poland. I recommend folks google searching stories about it and following those journalists and activists in Poland for the latest news. And check back to the lounge in the future for a run down of what went down. (psst, Poland had coal companies sponsor the event including have multiple coal displays…I’m not joking…goodness). There will be a lot to talk about, including some amazing efforts globally by the world’s youth to force action. Inspiring stuff, people.

Fourth National Climate Assessment

Washington Post

Pub Quiz

Today's Pub Quiz was on the human anatomy.

In Next Week’s Episode

Next week we’ll be talking with Gabriela Montejo-Kovacevich of the University of Cambridge. We'll get an inside look at her field work in South America studying a very interesting genus of butterflies, the Heliconians. Don't miss it!

In Closing

That concludes this episode of the Blue Streak Science Podcast.

If you have any suggestions or comments email us at podcast@bluestreakscience.com

You can subscribe to our show on Apple Podcasts, Spotify and any number of podcast directories.

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This show is produced by the Blue Streak Science team, and edited by Pro Podcast Solutions.

Our hosts today were Dr. Amrita Sule, Sophie McManus, and Tom Di Liberto.

I’m JD Goodwin.  

Thank you for joining us.

And remember…follow the science!


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