Global Warming Slowdown Attributed to Phase-Out of CFCs
By Tim Radford
What appears to be a slowdown in the rate of atmospheric warming this century may have a simple explanation, Mexican scientists say. It could be the consequence of protecting the ozone layer.
Scientists who looked at the whole history of climate in the twentieth century have come up with a new possible explanation for the apparent slowdown in global warming. It is because, they say, of the Montreal Protocol that banned chlorofluorocarbons (CFCs) and saved the ozone layer.
The ozone layer was the second great atmospheric crisis of the late twentieth century (the first involved the urban smog and acid rain that triggered clean air legislation in Europe and the U.S.). CFCs were the safe, enduring gases used as refrigerants: their only problem was that—once they reached the stratosphere—they unexpectedly began to destroy the ozone layer that screens out harmful ultraviolet light.
Within four years of the dramatic discovery of a huge “hole” in the ozone layer over the Antarctic, these gases were phased out, in a rare act of international agreement, by the 1989 Montreal Protocol.
But CFCs had a second unexpected property. They were greenhouse gases of unusual potency: molecule for molecule, one of them was rated at more than 17,000 times more effective at trapping infrared radiation than carbon dioxide. CFCs were released only in comparatively tiny quantities, but they were calculated to account for up to 24 percent of global warming.
Francisco Estrada of the National Autonomous University of Mexico and colleagues report in Nature Geoscience that they spotted the signal of the missing CFCs when they used statistical analysis to examine average temperature records in the two hemispheres from 1880 to 2010.
Tentative Results, Clear Pattern
Exercises such as these are not simple: the scientists had to find a way of eliminating natural cycles that keep the weather in a permanent pattern of change, and identify long-term trends that could be identified as evidence of human activity.
In the first place, for a mix of reasons, rates of change in the two hemispheres are out of step; in the second place there are natural cycles linked to ocean and atmospheric circulation such as the Atlantic Multidecadal Oscillation that are associated with extended periods of warming and cooling; in the third place things like greenhouse gas emissions are tied into cycles of economic growth, and affected again in many cases by legislation, perhaps to reduce the aerosols that make citizens cough and splutter, but that also block sunlight and have a mild cooling effect.
And to get the results that they did, the researchers had to use advanced statistical methods (for example, they say, the “Perron-Yabu testing procedure, valid with integrated or stationary noise”) that would baffle most of the human race.
So like all research results, the findings are tentative and published to provoke more research. But even so, the graphs in Nature Geoscience show a pattern of human influence in global average temperatures.
In the last century, the planet warmed overall by 0.8 degrees Celsius. In the trend discernible in the sometimes dramatic oscillations of temperature, there is evidence of a slowdown in this warming during two world wars, and the Great Depression of the 1930s, when world trade came to a standstill, factories closed everywhere and chimneys stopped smoking.
The authors see a pronounced rise in both greenhouse gas emissions and in global temperatures in the 1960s—the start of sustained global warming. But they also see a distinct slowdown that begins in the 1990s in response to the Montreal Protocol, which began the phase-out of the CFCs and the slow restoration of the ozone screen.
Slowdown Caused by Humans
The Montreal Protocol is not the only possible explanation for the apparent slowdown. There is also evidence that at least one sector of deep ocean is warming 15 times faster than at any time in the last 10,000 years, which suggests that ocean circulation may be carrying away the heat that meteorologists expected to record in the atmosphere.
Two scientists in October proposed that the slowdown in the rate of global warming could possibly be explained by a much longer-term natural cycle that nobody had yet identified: a climate signal could propagate across the northern hemisphere in a self-organising way, just as the so-called “stadium wave” propagates around a sports arena as excited spectators stand and sit down again.
They say in Climate Dynamics that such a phenomenon could be linked to a brake-and-accelerator pattern of influence of northern sea ice on atmosphere and ocean circulation.
If this pattern exists, it would explain why climate modellers had not predicted the present lull or slowdown in global warming. But the wave itself would have nothing to do with global warming, the two authors say. It would just offer a new perspective for climate science.
The Nature Geoscience paper, however, does once again confirm the link between average temperatures and greenhouse gas emissions. “Paradoxically the recent decrease in warming, presented by global warming skeptics as proof that humankind cannot affect the climate system, is shown to have a direct human origin,” the authors conclude.
Visit EcoWatch’s CLIMATE CHANGE page for more related news on this topic.
EcoWatch Daily Newsletter
The U.S. reported more than 55,000 new coronavirus cases on Thursday, in a sign that the outbreak is not letting up as the Fourth of July weekend kicks off.
- The U.S. Isn't in a Second Wave of Coronavirus – The First Wave ... ›
- Navajo Nation Has Highest Covid-19 Infection Rate in the U.S. ... ›
- U.S. Coronavirus Cases Top 2 Million as All 50 States Start ... ›
By Jason Bruck
Human actions have taken a steep toll on whales and dolphins. Some studies estimate that small whale abundance, which includes dolphins, has fallen 87% since 1980 and thousands of whales die from rope entanglement annually. But humans also cause less obvious harm. Researchers have found changes in the stress levels, reproductive health and respiratory health of these animals, but this valuable data is extremely hard to collect.
Researchers work with trained dolphins to learn more about their sensory abilities, seen here testing a dolphin's hearing. Jason Bruck / CC BY-ND
A Lot to Learn From Hormones<p>When sampling the blow, we are looking for hormones in mucus as these can be used to gauge psychological and physiological health. We are specifically interested in <a href="https://dx.doi.org/10.1371%2Fjournal.pone.0114062" target="_blank">hormones like cortisol</a> and <a href="https://doi.org/10.1016/j.ygcen.2018.04.003" target="_blank">progesterone</a>, which indicate stress levels and reproductive ability respectively, but can also help determine overall health.</p><p>Additionally, blow samples can detect <a href="https://dx.doi.org/10.1128%2FmSystems.00119-17" target="_blank">respiratory pathogens</a> in the lungs or nasal passages - blowholes evolved from noses after all.</p><p>This health analysis is especially important in areas with oil spills as the chemicals can cause hormonal problems that harm <a href="https://www.carmmha.org/investigating-how-oil-spills-affect-dolphins-and-whales/" target="_blank">development, metabolism and reproduction</a> in dolphins.</p><p>Hormone samples can provide scientists with valuable data, but collecting them from intelligent and unpredictable animals is challenging.</p>
Cetacean Collaborators<p>To build a drone that can stealthily collect spray from moving dolphins, we needed more data on their eyesight and hearing, and this is data that couldn't be collected in the wild nor simulated in a lab.</p><p>We worked with dolphins at facilities like Dolphin Quest in Bermuda, which provides guests opportunities to learn about dolphins while allowing <a href="https://dolphinquest.com/about-us/our-story/" target="_blank">scientists access to animals for noninvasive research</a>. Here the dolphins can swim away if they choose not to work with us, so we had to design the study like a game; the way a kindergarten teacher entertains a class. If the dolphins aren't interested, we don't get to do the science.</p><p>Over the course of hundreds of sessions, we sought to answer two questions: What can dolphins hear and what can they see around their heads?</p><p>To test dolphin hearing, we set up microphones and cameras to record dolphin behavior as we played drone noise in the air. We analyzed the responses to each noise – such as how many dolphins looked at the speaker – and used these as a proxy for their ability to hear the sounds.</p>
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="5f31daf07a652b8d64a093b993ee4e96"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/UjmQeH3vXHI?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
Robodolphin doesn't look like a real dolphin, but it doesn't need to in order to train our drone pilots. C.J. Barton / Oklahoma State University / CC BY-ND<p>To build robodolphin, we worked with dolphins trained to "chuff" or sneeze on command to measure spray characteristics. We used high-speed photography to see the dolphins' breath as it moved through the air. Then we conducted high resolution CT scans of a dolphin head and 3D-printed a replica of a nasal passage.</p><p>Now, we have a complete robodolphin and are tweaking its sprays to be nearly identical to the real thing. This will allow us to determine how close we need to get to collect the samples, and therefore, how quiet our drone needs to be.</p>
The replica dolphin blowhole was designed from a scan of a real blowhole passage, and the spray it produces closely matches the real thing. Alvin Ngo, Mitch Ford and CJ Barton / Oklahoma State University / CC BY-ND
A Bit of Practice, Then Into the Wild<p>In the next few months, we will test flights over robodolphin with existing drones to determine the timing and strategy for collection. From there, we will fabricate a low-noise drone that can fly fast enough and with sufficient maneuverability to capture samples from wild dolphins. Like a video game, we will use the visual field data to develop approach trajectories to stay in the visual blindspots.</p><p>We plan to test our drones on a truck-mounted robodolphin moving down a runway, then using a boat to simulate realistic conditions. The next steps will involve ocean testing with dolphins trained for open ocean swimming. These tests will determine if our devices can catch and hold the hormones as the drone flies back to a researcher's boat.</p><p>Finally, we will deploy the system to collect data on wild dolphins. Our first goal is to test resident dolphins – animals that live on the coasts and deal directly with boat and oil industry noise – which will allow us to learn more about stress resulting from human impacts.</p><p>Those samples are a way off, but if all goes well we will have a specially built drone capable of flying long distances and capturing samples undetected in a few years. The samples collected will allow researchers to do better science with impact on the animals they study.</p>
- Drone Footage Captures Rare Finless Porpoises in Hong Kong ... ›
- Brazil's Amazon River Dolphin Faces Extinction After Fishing ... ›
- 10 Surprising Dolphin 'Superpowers' - EcoWatch ›
Sunscreen pollution is accelerating the demise of coral reefs globally by causing permanent DNA damage to coral. gonzalo martinez / iStock / Getty Images Plus
On July 29, Florida Governor Ron DeSantis signed into law a controversial bill prohibiting local governments from banning certain types of sunscreens.
- Your Guide to Reef Friendly Sunscreens - EcoWatch ›
- Hundreds of Sunscreens Don't Work or Have Unsafe Ingredients ... ›
- FDA Study: Sunscreen Chemicals Seep Into the Bloodstream ... ›
By Kelli McGrane
Oat milk is popping up at coffee shops and grocery stores alike, quickly becoming one of the trendiest plant-based milks.
- Is Oat Milk Gluten-Free? - EcoWatch ›
- What Nutritionists Think About Starbucks' Three New Plant-Based ... ›
- 6 Alternatives to Milk: Which Is the Healthiest? - EcoWatch ›
"Emissions from pyrotechnic displays are composed of numerous organic compounds as well as metals," a new study reports. Nodar Chernishev / EyeEm / Getty Images
Fireworks have taken a lot of heat recently. In South Dakota, fire experts have said President Trump's plan to hold a fireworks show is dangerous and public health experts have criticized the lack of plans to enforce mask wearing or social distancing. Now, a new study shows that shooting off fireworks at home may expose you and your family to dangerous levels of lead, copper and other toxins.
- No Social Distancing or Mask Requirement at Trump's Mt ... ›
- Trump's Fireworks Show at Mt. Rushmore Is a Dangerous Idea, Fire ... ›
By Ashutosh Pandey
Billions worth of valuable metals such as gold, silver and copper were dumped or burned last year as electronic waste produced globally jumped to a record 53.6 million tons (Mt), or 7.3 kilogram per person, a UN report showed on Thursday.
Environmental and Health Hazard<p>Experts say e-waste, which is now the world's fastest-growing domestic waste stream, poses serious environmental and health risks.</p><p>Simply throwing away electronic items without ensuring they get properly recycled leads to the loss of key materials such as iron, copper and gold, which can otherwise be recovered and used as primary raw materials to make new equipment, thereby reducing greenhouse gas emissions from extraction and refinement of raw materials.</p><p>Refrigerants found in electronic equipment such as fridge and air conditioners also contribute to global warming. A total of 98 Mt of CO2-equivalents, or about 0.3% of global energy-related emissions, were released into the atmosphere in 2019 from discarded refrigerators and ACs that were not recycled properly, the report said.</p><p>E-waste contains several toxic additives or hazardous substances, such as mercury and brominated flame retardants (BFR), and simply burning it or throwing it away could lead to serious health issues. Several studies have linked unregulated recycling of e-waste to adverse birth outcomes like stillbirth and premature birth, damages to the human brain or nervous system and in some cases hearing loss and heart troubles.</p><p>"Informal and improper e-waste recycling is a major emerging hazard silently affecting our health and that of future generations. One in four children are dying from avoidable environmental exposures," said Maria Neira, director of the Environment, Climate Change and Health Department at the World Health Organization. "One in four children could be saved, if we take action to protect their health and ensure a safe environment."</p>
Europe Leads the Way<p>While most of the e-waste was generated in Asia (24.9 Mt) in 2019, Europe led the charts on a per person basis with 16.2 kg per capita, the report said.</p><p>But the continent also recorded the <a href="https://www.dw.com/en/the-eu-declares-war-on-e-waste/a-51108790" target="_blank">highest documented formal e-waste collection and recycling</a> rate at 42.5%, still below its target of 65%. Europe was well ahead of the others on this front. Asia ranked second with 11.7%.</p><p>The authors said while more that 70% of the world's population was covered by some form of e-waste policy or laws, not much was being done toward implementation and enforcement of the regulations to encourage the take-up of a collection and recycling infrastructure due to lack of investment and political motivation.</p><p>"You have to think about new economic systems," said Kühr.</p><p>One approach could be that consumers no longer buy the products, but only the service they offer. The device would remain the property of the maker, who would then have an interest in offering his customers the best service and the necessary equipment. The maker would also be interested in designing his products in such a way that they are easier to repair and easier to recycle, Kühr said.</p>
- Dangerous Chemicals From E-Waste Found in Black Plastics From ... ›
- Electronic Waste Study Finds $65 Billion in Raw Materials ... ›
- Electronic Waste: New EU Rules Target Throwaway Culture ... ›
- COVID-19 Masks Are Polluting Beaches and Oceans - EcoWatch ›
- Plastic Packaging Use Increases During the Coronavirus - EcoWatch ›
- Coronavirus Worsens Thailand's Plastic Waste Crisis - EcoWatch ›
- Coronavirus Plastic Waste Polluting the Environment - EcoWatch ›