Washington (CNN)Vice President Mike Pence on Sunday wouldn’t say if he views the global climate crisis as a threat to the United States.
Researchers claim cosmic particles bombarded Earth’s surface at such high levels forests turned to savannah
Exploding stars 2.6 million years ago may have caused ancient humans to walk upright, a new scientific paper claims.
Cosmic particles from these supernovae bombarded Earth’s surface at such high levels that they caused global forest fires, researchers from the University of Kansas suggest.
This led to the creation of large swathes of savannahs in places that would previously have been forested. Early hominins in northeast Africa had to learn to walk on two legs to cross these vast areas, according to the study, published in the Journal of Geology.
The theory was laid out by a team led by physicist Professor Adrian Melott in an attempt to join together different strands of research.
“It is thought there was already some tendency for hominins to walk on two legs, even before this event. But they were mainly adapted for climbing around in trees,” he said.
“After this conversion to savannah, they would much more often have to walk from one tree to another across the grassland, and so they become better at walking upright. They could see over the tops of grass and watch for predators.”
Professor Melott arrived at this hypothesis by drawing on research about historic supernovae and evidence for the impact they had on Earth. Ancient seabed deposits of iron-60 isotopes – radioactive forms of iron – provided a crucial clue.
Professor Melott said these materials must have arrived on Earth from a supernova, which would have exploded 163 light years away during the transition from the Pliocene Epoch to the Ice Age.
“We calculated the ionisation of the atmosphere from cosmic rays which would come from a supernova about as far away as the iron-60 deposits indicate,” he said.
“We contend it would increase the ionisation of the lower atmosphere by 50-fold. Usually, you don’t get lower-atmosphere ionisation because cosmic rays don’t penetrate that far, but the more energetic ones from supernovae come right down to the surface – so there would be a lot of electrons being knocked out of the atmosphere.”
They suggest ionisation in the lower atmosphere meant there were more pathways for lightning strikes which led to widespread fires.
“The observation is that there’s a lot more charcoal and soot in the world starting a few million years ago. It’s all over the place, and nobody has any explanation for why it would have happened all over the world in different climate zones. This could be an explanation,” he said.
“That increase in fires is thought to have stimulated the transition from woodland to savannah in a lot of places – where you had forests, now you had mostly open grassland with shrubby things here and there.”
Professor Melott said no similar event was expected to happen any time soon. The nearest star capable of exploding into a supernova in the next million years is Betelgeuse, which is 652 light years from Earth.
“Betelgeuse is too far away to have effects anywhere near this strong,” he said.
At the end of last year Professor Melott led another study that found supernovae 2.6 million years ago could have swept Earth’s prehistoric oceans wiping out creatures like the giant shark known as the Megalodon.
His research suggested that particles from these exploding stars could have caused cancers in large marine mammals to spike.
People are too complacent about the asteroid threat for Bill Nye’s liking.
The former TV “Science Guy,” who currently serves as CEO of the nonprofit Planetary Society, warned that catastrophic impacts like the one that offed the dinosaurs 66 million years ago are not confined to the past.
“The Earth is going to get hit with another [big] asteroid,” Nye said yesterday (May 2) at the International Academy of Astronautics’2019 Planetary Defense Conference in College Park, Maryland.
“The problem is, we don’t know when,” he added. “It’s a very low probability in anyone’s lifetime, but it’s a very high-consequence event. If it happens, it would be like control-alt-delete for everything.”
Unlike the dinosaurs, however, we don’t just have to sit around and wait for doom to rain down on us. We can do something about the asteroid threat — and we should start prepping for it now, Nye stressed.
The first step is to find the dangerous space rocks. There’s good news on this front: NASA scientists think they’ve already discovered more than 90% of the potential civilization-enders — near-Earth asteroids at least 0.6 miles (1 kilometers) wide — and none of these mountain-size space rocks pose a threat for the foreseeable future.
But there are lots of undiscovered asteroids zooming through near-Earth space that could do serious damage on a local scale — wiping out an area the size of a state, for example. So, it would behoove us to get some better detection tools online, Nye said.
Such help is coming, and soon. For instance, the Large Synoptic Survey Telescope, a big instrument set to start observing the heavens next year from Chile, will likely be able to discover and catalog 80% to 90% of potentially hazardous asteroids at least 460 feet (140 meters) wide, project team members say.
And NASA is considering launching a dedicated asteroid-hunter called the Near-Earth Object Camera. This proposed mission would scan for space rocks in infrared light, spotting their heat signatures in the darkness.
Coordination is the next step after detection, Nye said. A big asteroid hurtling toward Earth would be a global issue, so the international community would have to work together to deal with it.
And we’d have several options at our disposal. If we had enough warning time — years or, preferably, decades — we could launch a probe to fly alongside the asteroid, gradually nudging the rock off course via a gravitational tug. This “gravity tractor” craft would ideally boost its pull by plucking a big boulder off the asteroid, said NASA Chief Scientist Jim Green, who participated in yesterday’s event with Nye.
If we were pressed for time, we could slam one or more spacecraft into the asteroid, knocking it onto a benign trajectory through brute force. Or we could detonate a nuclear weapon near the rock, vaporizing much of its surface. The resulting mass loss, and the flow of material off the asteroid, would change the rock’s path, experts say. And the shock wave from the blast might do the trick by itself, Nye said.
Nye also mentioned the “Laser Bees” strategy, which involves sending a swarm of small spacecraft out to the potentially dangerous asteroid. Each little probe would focus a laser beam on the same spot on the rock, vaporizing material and causing a jet to erupt. This jet would serve as a sort of engine that would push the asteroid onto a different path.
During his portion of the presentation, Green highlighted the many things we can learn from asteroids — they’re time capsules from the dawn of the solar system, after all, and carbon-rich rocks may have helped life get started on Earth — and their potential benefits for exploration. Tapping into asteroid resources could make voyaging spacecraft and astronauts more self-sufficient and improve life here on Earth as well, he said.
But Green agreed with Nye that the space-rock threat is real: There are catastrophic impacts in our future if we don’t do something about them.
“It’s not a matter of if; it’s only a matter of when,” Green said.
President Trump’s pick for leading a climate change panel is notorious for denying the science behind human-caused global warming. We dive into the counter-arguments on climate change.USA TODAY, Just the FAQs
Climate change is real and increasingly a part of our daily lives. New research and studies out in just the past six months highlight the latest facts about the human-caused shift to our global weather systems and its effects on our planet.
First among them, there’s no longer any question that rising temperatures and increasingly chaotic weather are the work of humanity. There’s a 99.9999% chance that humans are the cause of global warming, a February study reported. That means we’ve reached the “gold standard” for certainty, a statistical measure typically used in particle physics.
The mechanism is well understood and has been for decades. Humans burn fossil fuels such as oil, coal and gas, which release carbon dioxide (CO2), methane and other gases into the Earth’s atmosphere and oceans. CO2 is the greenhouse gas that’s most responsible for warming.
Want news from USA TODAY on WhatsApp? Click this link on your mobile device to get started
Study lead author Benjamin Santer of the Lawrence Livermore National Laboratory in Livermore, California, told Reuters that “the narrative out there that scientists don’t know the cause of climate change is wrong.”
Hottest on record
The past five years have been the five warmest since record-keeping began in the late 1800s. The Earth has experienced 42 straight years (since 1977) with an above-average global temperature, according to the National Oceanic and Atmospheric Administration.
Based on five separate data sets that keep track of the Earth’s climate, the global average temperature for the first 10 months of 2018 was about 1.8 degrees above what it was in the late 1800s. That was when industry started to emit large amounts of greenhouse gases into the atmosphere.
Australia experienced record summer heat in January of this year. The town of Port Augusta reached the hottest day since record-keeping began in 1962 with a temperature of 121, according to the Guardian.
The heat was so intense it caused bats to fall from trees, according to the Australian Broadcasting Corporation.
Carbon dioxide up 46%
Increasing amounts of carbon dioxide and other gases being released into the atmosphere by industry, transportation and energy production from burning fossil fuels are enhancing what’s known as the planet’s natural greenhouse effect.
Carbon dioxide is the most prevalent among all greenhouse gases produced by human activities, attributed to the burning of fossil fuels.
The atmospheric carbon dioxide level for March was 411.97 parts per million and continue to rise. It has now reached levels in the atmosphere not seen in 3 million years.
That’s an increase of 46% from just before the Industrial Revolution in the 1800s, when CO2 levels were around 280 parts per million. Levels began to rise when humans began to burn large amounts of fossil fuels to run factories and heat homes, releasing CO2 and other greenhouse gasses into the atmosphere.
Scientists say to keep a livable planet, we need to cut the level to 350 parts per million.
A consequence of higher temperatures is the melting of the polar ice caps, which is causing sea levels to rise. The world’s oceans have risen about an inch in the past 50 years due to melting glaciers alone, a study published this month in the journal Naturefound.
Global warming has caused over 3 trillion tons of ice to melt from Antarctica in the past quarter-century and tripled ice loss there in the past decade, another study, released in June, said.
Killing Americans, costing billions
Extreme weather events exacerbated in part by climate change killed almost 250 Americans and cost the nation at least $91 billion in 2018, according to the National Oceanic and Atmospheric Administration.
Unusual warmth in the U.S. West in 2018 contributed to a disastrous wildfire season that killed dozens of people. In monetary terms, western states endured their costliest wildfire season on record: $24 billion in damage.
Hurricanes Michael, resulting in $25 billion damages, and Florence, with $24 billion in costs, were the other two big weather disasters in 2018.
New York City with Arkansas’ weather
If the amount of carbon dioxide in the atmosphere isn’t lowered, temperatures will continue to increase. A study released in February mapped just how different the climate in U.S. cities will be in 60 years if greenhouse gas emissions continue.
The Nature study found that on average, the future climate will resemble the one experienced by an area 528 miles to the south today.
That means that by 2080, New York City could have the climate of Arkansas. Minneapolis could be more like Kansas and San Francisco could have weather closer to Los Angeles than its current foggy climate. Other cities further south could experience climates with no modern equivalent in North America.
“The children alive today, like my daughter who is 12, they’re going to see a dramatic transformation of climate. It’s already underway,” said study lead author Matt Fitzpatrick of the University of Maryland’s Center for Environmental Science.
The new Netflix series Our Planet begins, of all places, on the moon. Rest assured that the camera soon reveals a view of our tiny, stunning home planet, where it stays grounded for the next eight episodes. It’s an exercise in perspective. As the astronauts on the Apollo mission first found out 50 years ago, that distant view helps you see that our fragile planet has limits. It’s a precious object.
David Attenborough, the 92-year-old naturalist famous for his warm, authoritative half-whisper, immediately clears up any concerns that Our Planet is your typical nature show. As a polar bear and its cub amble across icy terrain, Attenborough explains that wildlife populations have plunged, on average, by 60 percent over the last 50 years. “For the first time in human history,” he says, “the stability of nature can no longer be taken for granted.” (Cue melting ice crashing into the sea.)
Our Planet takes you on a trip to every type of landscape and seascape on Earth. The icy Antarctic, the deep jungle in Borneo, the Arabian desert, the coral reefs of Australia. It has all the familiar scenes of frolicking wildebeest, feasting flamingos, and weird bird mating dances you’re used to seeing from the Planet Earth canon, but unlike its predecessors, it’s punctuated by frequent reminders that global catastrophe is unfolding. Half of the world’s shallow coral reefs have already perished, and the rest could disappear within a few decades. Each year we lose nearly 15 million hectares of tropical forest, an area larger than Illinois. And by 2040, the Arctic Ocean will be mostly ice-free.
“We are entering a new geological era, not as in the past when changes happened over millions of years, not even over thousands of years or centuries, but within decades — within my lifetime,” Attenborough writes in the coffee table book that accompanies the documentary. “These changes are as rapid and as great as when the planet was struck by an asteroid.”
The show is part of an emerging genre of wildlife documentary that tackles conservation and climate change in tandem. The new National Geographic seriesHostile Planet, narrated by Bear Grylls of Man vs. Wild, portrays animals toughing out searing heat, parched landscapes, and fractured ice in the most extreme environments on Earth. Attenborough also narrated a documentary coming out this spring called Climate Change: The Facts on BBC One.
For a show about our shifting environment, it’s curious that Our Planet’s carefully constructed opening — and the entire first episode — fails to mention “climate change” by name. (The later episodes don’t shy away from the phrase.) The opening episode, which explains how far-flung habitats on Earth are all connected, was possibly the hardest one to get right, said Alastair Fothergill, the series producer, in an email.
“We felt it critical for the whole series that the balance between entertainment, education, and environmental messaging was just right,” he said. “We need millions of people worldwide to watch this series, and we need to ensure we do not alienate the audience.”
It’s a tough task, since the episodes are filled with sobering facts. Dismal statistics spell out the fate of the unsuspecting animals living their lives onscreen. As you watch fuzzy orangutans swing between trees in northern Sumatra, for example, Attenborough says you could be looking at the last ones to live in the wild. Deforestation has led to the demise of 100 orangutans a week, he says, by turning their jungle home into expanses of palm trees grown for their oil.
Those responsible for all this forest-clearing, poaching, and destruction spend most of the series offstage. The only time people show up is in the “Coastal Seas” episode, which illustrates overfishing by showing fishermen at work in their boats. Only a few images of human activity made the cut, Fothergill said. But they’re all the more powerful as a result.
The episodes come with mini science lessons. You’ll learn how Arctic sea ice acts as a “protective white shield” for the planet, keeping the earth cool by reflecting the sun’s energy back into space, and that Earth is losing that shield, a feedback loop that accelerates warming. You’ll also learn about the science of coral bleaching and the amazing carbon-sucking powers of forests and seagrass.
And, as in any good nature series, you’ll probably find one thing that blows you away. For me, in Blue Planet II, it was the toxic lakes inside the ocean. In Our Planet, it’s that the underside of that pristine-looking Antarctic sea ice is covered in algae, forming the base of an ecosystem that Attenborough describes as “the polar equivalent of the great grasslands.”
It’s not all grim. Siberian tigers are slowly coming back from the brink of extinction; blue whales and humpback whales have made remarkable recoveries thanks to international agreements around saving them. It’s a reminder of what human cooperation is capable of accomplishing when we’re actually able to cooperate … or when we just leave things alone.
The final episode tells the story of Europe’s strangest wildlife recovery. It takes place in the radioactive exclusion zone around Chernobyl, Ukraine. Twenty years after 100,000 people evacuated, the fallout zone held animal populations similar to those in the wilder parts of Europe, Attenborough says; now, wildlife populations there are more profuse than in the surrounding nature preserves or national parks. Bison, elk, and red deer wander among the ruins of buildings as wolves and lynx patrol the forest that’s regrown in the former suburbs.
“They may be radioactive,” the Our Planet book says, “but they are having a ball.”
Society should also acknowledge that those who choose not to have children are making a valuable contribution to a sustainable future
The global population is growing rapidly, while the resources we depend on to live are dwindling. If you consider the footprint each person makes on the world – in terms of food and water consumed, electricity and gas used, and waste produced – the challenge of improving living standards while protecting natural resources and the environment is striking. The question of human population size is fundamentally one of sustainability, and in that so is the choice to have children.
Rather than being taboo, being childfree is something that should be celebrated and valued. The childfree do more for our environment than any campaign. In the UK our electricity use per capita is 5,407 kWh – it’s nigh on impossible to make up for the environmental footprint of having a child by remembering to switch off the lights. Finite resources mean we must consider our consumption now, what living standards are acceptable, and how to maintain the ecosystems on which we depend and how many of us there are.
Women are now as likely to be childless as to have three children. As social norms shift, a childfree lifestyle has become increasingly attractive, with career taking centre-stage for many thirtysomethings. Add to this rising living costs and you can see the clear benefits of not having children: the £250,000 required to raise each child is a challenge even for the most well-off.
In recent months, there has been ongoing speculation about those who do not have children: let’s call them ‘the childfree’, whether it’s Jennifer Aniston’s “baby bump” or conversations in the corridors of Westminster. Andrea Leadsom believed her credentials as a mother made her Prime Minister in-waiting, while Labour leadership candidate Owen Smith’s self-proclaimed normality stemmed from his “wife and two kids”. Being childfree is one of the oldest taboos, and it comes with a host assumed connotations: being less invested in the future or being ‘abnormal’ are but two.
There are, however, signs that things are changing. Our new Prime Minister became not only the second woman to fill the role, but the first to do so without being a mother. Leadsom’s alienating language backfired: the media and Twitterati rounded on those burnishing their ‘normal family’ credentials. It was May’s experience and competency that saw her become Prime Minister – her childfree status was, in the end, irrelevant.
Of course, having a family will always be a central part of life for many. The people who wish to have children but cannot need our empathy and support. But society should also acknowledge that those who choose not to have children are making a valuable contribution to a sustainable future.
Our numbers have doubled in the last 50 years, transforming Earth into a ticking time bomb. Climate change is one devastating symptom of this surge. Population growth increases the number of wealthy carbon emitters and poorer climate change victims, while hampering mitigation and adaptation efforts.
Beyond environmental concerns, political instability, civil conflict and mass migration are an inevitable consequence. Young populations, high birth rates and rising life expectancy mean that, for instance, Africa’s population alone is expected to rise from one to four billion this century. While a global response is needed, industrialised countries like Britain, which consume more than their fair share of resources, must lead by example.
With the steady erosion of the childfree taboo, it is time to reopen the debate surrounding population growth and sustainability, educate young people about mindful consumption, and advocate improvements to family planning, sex education and women’s rights.
I will close with the wise words of actress and model Cameron Diaz: “I think women are afraid to say that they don’t want children because they’re going to get shunned. But I think that’s changing too now. I have more girlfriends who don’t have kids than those that do. And, honestly? We don’t need any more kids. We have plenty of people on this planet.”
Simon Ross is chief executive of Population Matters, a UK-based membership charity that addresses population size and environmental sustainability
Q. How come the huge impact of our population growth on climate change doesn’t get more attention when we talk about how to take action against warming?
— Too Many Humans, Too Little Time
A. Dear TMHTLT,
There’s long been a contingent of environmentalists who love to point to the world’s population as a major factor in humans’ self-destruction. The logic seems basic: Climate change is caused by humans, so fewer humans should limit the harm of climate change.
The “optimal” global population to sustain ecosystems is considered to be between 1 and 2 billion. The actual population at present is a bit more than 7.5 billion.
The issue of how you arrive at fewer humans is decidedly less basic. Some entity has to dictate which humans get to produce more humans — or in an even more macabre scenario, which humans stay and which humans go. The way that societies have made that decision, historically, is by ranking the worth of different groups — usually by ethnicity, often by sexuality, frequently by mental and physical ability — and sterilizing those deemed to be of lower value. In the U.S. alone, Latinos, Native Americans, African-Americans, and the mentally ill and disabled have all been victims of this dehumanizing practice, shockingly all as recently as the 1970s.
“A main argument for why those coerced sterilizations were done was to alleviate the pressure that population growth was putting on state resources, because these groups were disproportionately receiving welfare,” Jade Sasser, a professor of feminist political ecology at the University of California, Riverside, and author of On Infertile Ground: Population Control and Women’s Rights in the Era of Climate Change, told me.
That argument goes directly back to the English economist Thomas Malthus, who wrote in the late-18th century that unchecked population growth would bring with it food shortages, illness, and conflict, she explained. “And it actually exacerbates inequality because it suggests that the poor and people of color are responsible for the inequalities that actually constrain their lives and their choices.”
The man who many count as responsible for bringing Malthusian logic into mainstream environmental theory is Stanford University conservation biologist Paul Ehrlich, co-author of the controversial book “The Population Bomb.” (His wife, Anne, is his frequent collaborator and an uncredited co-author on that seminal work.) I called him to try to answer how much we can blame overpopulation for climate change.
Fifty years after his book’s release, Ehrlich still believes that population is an under-recognized threat in environmental degradation because it naturally drives up consumption. In collaboration with John Holdren, who went on to serve as President Barack Obama’s senior science and technology advisor, Ehrlich developed the “IPAT equation” in the 1970s:
Environmental impact (I) = population (P) x affluence or, essentially, propensity to consume (A) x technology (T).
Looking at the equation, it stands to reason that if we are able to greatly reduce consumption and greatly improve the efficiency of our technology, wouldn’t that allow us to potentially forgo population control?
“It certainly would carry less weight,” Ehrlich said. “But the problem is that the three together now are on a doomsday path. I don’t see the slightest chance of us changing to avoid what’s coming. The idea that you can just ignore how many people there are and get a technological fix to worry about food or climate or war or so on — it’s as illogical as religion.”
It likely comes as no surprise that in the half-century since IPAT’s development a new generation of academics has made modifications to it. I found one in a lecture from an industrial ecology course taught at Dartmouth College.
This alternate version replaces affluence with per capita Gross Domestic Product, the value of all goods and services in a particular economy divided by its total population. The equation reads:
Environmental impact = GDP per capita x population x technology.
Population cancels out, of course, and you end up with:
Environmental impact = GDP x technology.
This modified IPAT can be used to show how different countries contribute to climate change through their energy use — there are wealthy countries with relatively clean technology (like Denmark, where wind energy is dominant), middle-income countries with high-polluting technology (like coal-dependent India), and low-income countries who consume very little but also have regressive technology (like Somalia, which relies heavily on diesel generators).
In our conversation, Ehrlich suggests we should aspire to have a system where everyone consumes the same amount. At the same time, he says, we should work toward making that consumption as sustainable as possible. But, he adds, “I see no way you can solve problems of equity without the rich giving up a lot of what they do to make room for the poor to do better.”
Without rapid development of clean-powered circular economies and a massive transfer of wealth, we end up back with population being an active factor in climate change.
OK, so how do you choose which people have to go? Imagine the United States Congress — largely white people, many of whom enjoy great wealth, but generally all of whom consume plenty (in some cases thanks to their support of dirty technologies). If those people are making the rules on population control in the U.S., do you think they’re going to advocate for the rights of communities that aren’t like most of its members?
In fact, the one point that both the reproductive justice community and neo-Malthusians can agree on is that the provision of voluntary, universal access to birth control is a bare-minimum human right. In the United States, one of the highest-emitting countries in the world, it’s misleading to discuss population-based policies — such as China’s one-child policy — as a reasonable solution to climate change when access to reproductive healthcare and any number of should-be basic resources here is so uneven.
“There are those environmentalists who are saying it’s not about voluntary access to birth control, it’s about creating demand and convincing people to have fewer children,” said Sasser, the UC Riverside professor. “I find that argument frustrating because the poor tend to use far fewer polluting resources than the wealthy, and until we really get to a place in which those kinds of social inequalities are eliminated, I don’t think we should be targeting the poor for lowering their resource consumption. It’s based on a blindness to inequalities that exist throughout the world.”
So my answer to your question, TMHTLT, is this: Talking about population as the primary cause of climate change is like talking about food as the primary cause of obesity. You can’t have obesity without food. (I mean, you can’t survive long enough to be obese without food.) But it’s not always the primary cause of obesity. There’s also systemic lack of access to healthy food, poor quality healthcare, genetic illness, and even environmental factors.
Simply limiting food without addressing any of the other factors doesn’t guarantee an improvement in the overall health of the person who is obese. Similarly, narrowly focusing on population without making incredible efforts to reduce our consumption and improve our technology is irresponsible.
“The narrative out there that scientists don’t know the cause of climate change is wrong. We do.”
No, We’re Sure
New analysis of 40 years’ worth of satellite data shows that it’s a near-certainty that humanity is actively causing global climate change.
Climate deniers often claim, in the face of overwhelming evidence, that the planet is heating up and natural disasters are becoming more intense and common just because that’s the way it is — incorrectly insisting that humanity’s love affair with fossil fuels has nothing to do with it. Now, scientists say the chances that that’s true are just one in a million.
Yep, Pretty Sure
According to the research by scientists at California’s Lawrence Livermore National Laboratory, that’s because climate data has now reached a so-called “gold standard” of scientific evidence — there’s only a one in a million chance that ongoing climate change could have been caused by anything other than humanity, reportsReuters.
“The narrative out there that scientists don’t know the cause of climate change is wrong,” Benjamin Santer, the scientist who led the research, told Reuters. “We do.”
The scientific research process almost never eradicates uncertainty: researchers test their hypotheses to get a better understanding of the world, but there’s almost always some other factor out there that could have impacted their findings. In other words, a gold standard is not something that’s taken lightly.
The new analysis looked at the three largest satellite data sets used by climate scientists. It shows that two of those data sets reached the gold standard of certainty that humanity causes climate change back in 2005, and the third did in 2016.
That level of certainty, highly uncommon in scientific research, makes humanity’s impact on the planet very clear. And now we have to figure out what to do about it.
“Humanity cannot afford to ignore such clear signals,” reads the analysis.
READ MORE: Evidence for man-made global warming hits ‘gold standard’: scientists [Reuters]
More on climate change: Climate Change Is Eliminating Clouds. Without Them, Earth Burns