Atmospheric rivers expected to prompt heavier future flooding
Atmospheric rivers are long jet streams of air that carry large amounts of water vapor. They are often called “rivers in the sky” and can fuel storms that cause disastrous amounts of flooding due to the high levels of water vapor present in the air streams.
In early 2017, California and much of the U.S. west coast was battered with severe flooding from atmospheric river storms.
A new NASA study examined the impact that climate change will have on atmospheric rivers around the world in an effort to provide a better understanding of the weather events.
According to NASA’s Jet Propulsion Laboratory in California, atmospheric river research was previously limited to either the western United States or Europe. Different methods and results meant that climatologists were not able to compare studies or predict atmospheric river intensity across the globe.
But this new study provides a method for predicting and evaluating the impacts of climate change on atmospheric river storms on a global scale, as opposed to isolated to a single region.
The results, recently published in the journal Geophysical Research Letters, project that although atmospheric rivers may slightly decline in numbers, the frequency and intensity of atmospheric river storms will almost double.
For the study, NASA researchers used global climate projections for the 21st century that were developed for the Intergovernmental Panel on Climate Change as well as an algorithm designed to detect atmospheric rivers around the world.
The algorithm calculates the length, width, and amount of water vapor present in any given atmospheric river from model simulations.
After applying the algorithm to both real-world observations and model simulations of climate for the 20th century, the researchers were able to show that model simulations accurately represented real-world data and events.
Next, the researchers used the algorithm to predict atmospheric river events for the late 21st century in order to compare the effects of climate change on these weather events.
The results showed that increases in global temperature and climate change would impact atmospheric rivers and intensity the frequency of storms even though the number of actual rivers would decrease.
“The results project that in a scenario where greenhouse gas emissions continue at the current rate, there will be about 10 percent fewer atmospheric rivers globally by the end of the 21st century,” said Duane Waliser, the study’s lead author. “However, because the findings project that the atmospheric rivers will be, on average, about 25 percent wider and longer, the global frequency of atmospheric river conditions — like heavy rain and strong winds — will actually increase by about 50 percent.”
Now, because of this study, researchers and climatologists have a uniform way to study climate change and its effect on atmospheric rivers which will be critical for the regions already affected by heavy flooding from atmospheric river fueled storms.
Hurricanes will get stronger and wetter with climate change
A team of scientists led by the National Center for Atmospheric Research (NCAR) is reporting on how past hurricanes would behave under the climate change conditions predicted by the end of this century. Each of the 22 storms analyzed for the study showed unique changes, but the hurricanes became longer, more intense, and much wetter on average.
Hurricane Ike, which devastated regions of the Gulf Coast and claimed over 100 lives, would linger for 17 percent longer, have 13 percent stronger winds, and would be 34 percent wetter under the future climate conditions.
Other storms were found to be slightly weaker or slightly faster, but none were found to be drier. Across all of the simulated storms, rainfall increased dramatically.
“Our research suggests that future hurricanes could drop significantly more rain,” said lead author and NCAR scientist Ethan Gutmann. “Hurricane Harvey demonstrated last year just how dangerous that can be.”
Hurricane Harvey dumped more than four feet of rain in some regions and caused devastating flooding across the Houston area.
The researchers ran the Weather Research and Forecasting (WRF) model at a high resolution across the United States over two 13-year periods. The first model simulated weather from between 2000 and 2013, and the second simulated the same weather patterns with temperatures boosted by five degrees Celsius.
“Some past studies have also run the WRF at a high resolution to study the impact of climate change on hurricanes, but those studies have tended to look at a single storm, like Sandy or Katrina,” explained Gutmann.
“What we find in looking at more than 20 storms is that some change one way, while others change in a different way. There is so much variability that you can’t study one storm and then extrapolate to all storms.”
Overall, the simulated storms had six percent stronger average maximum wind speeds and moved about nine percent more slowly. In addition, average rainfall rates were 24 percent higher.
“This study shows that the number of strong hurricanes, as a percent of total hurricanes each year, may increase,” said co-author Ed Bensman. “With increasing development along coastlines, that has important implications for future storm damage.”
The research is published in the Journal of Climate.
The Earth’s climate could increase by 4 degrees by 2084
The Paris Agreement of the United Nations is a global effort to prevent an increase in the Earth’s climate of 2°C. Almost every country on the planet has agreed to do what it takes to prevent this level of warming becoming a reality – minus the United States, the only country to withdraw. But now, a collaborative research team from China has published a new analysis that predicts the Earth’s climate could increase by 4°C by 2084, compared to pre-industrial levels.
Researcher Dabang Jiang of the Institute of Atmospheric Physics of the Chinese Academy of Sciences and his team used the parameters of a scenario in which there was no mitigation of rising greenhouse gas emissions. They compared 39 coordinated climate model experiments from the fifth phase of the Coupled Model Intercomparison Project, which creates and reviews climate models in order to ensure the climate simulations are as accurate as possible.
The results showed that most models project an increase of 4°C as early as 2064 and as late as 2095 in the 21st century.
“A great many record-breaking heat events, heavy floods, and extreme droughts would occur if global warming crosses the 4 °C level, with respect to the preindustrial period,” says Jiang. “The temperature increase would cause severe threats to ecosystems, human systems, and associated societies and economies.”
This temperature increase is a result of more annual and seasonal warming over land than over the ocean, and significant warming in the Arctic. Precipitation would likely increase in the Arctic and the Pacific, and the variability of temperature throughout a year would be lower in the tropics and higher in the polar regions.
“Such comparisons between the three levels of global warming imply that global and regional climate will undergo greater changes if higher levels of global warming are crossed in the 21st century,” says Jiang.
The research team is continuing to study the changes that are associated with a 4°C increase in extreme climates. “Our ultimate goal is to provide a comprehensive picture of the mean and extreme climate changes associated with higher levels of global warming based on state-of-the art climate models, which is of high interest to the decision-makers and the public,” says Jiang.
Antibiotic resistance has been linked to climate change
The growing issue of antibiotic resistance has now been linked to climate change. A team of epidemiologists led by Harvard Medical School discovered that higher local temperatures are associated with increased antibiotic resistance in common bacterial strains.
Study lead author Derek MacFadden is an infectious disease specialist at Boston Children’s Hospital.
“The effects of climate are increasingly being recognized in a variety of infectious diseases, but so far as we know this is the first time it has been implicated in the distribution of antibiotic resistance over geographies,” said MacFadden.
“We also found a signal that the associations between antibiotic resistance and temperature could be increasing over time.”
According to the Centers for Disease Control and Prevention, antibiotics are unnecessarily prescribed around 30 percent of the time, which was previously believed to be the cause of rising antibiotic resistance.
In the current study, the team used hospital and lab data from between 2013 and 2015 to examine antibiotic resistance in E. coli, K. pneumoniae and S. aureus. The investigation included more than 1.6 million bacterial specimens from 223 facilities across 41 states.
The study revealed that an increase in temperature of 18 degrees Fahrenheit boosted antibiotic-resistant strains of K. pneumoniae by 2.2 percent, S. aureus by 3.6 percent, and E. coli by 4.2 percent.
“Estimates outside of our study have already told us that there will already be a drastic and deadly rise in antibiotic resistance in coming years,” said co-senior author John Brownstein.
“But with our findings that climate change could be compounding and accelerating an increase in antibiotic resistance, the future prospects could be significantly worse than previously thought.”
The team also found a link between antibiotic resistance and population density.
“Population growth and increases in temperature and antibiotic resistance are three phenomena that we know are currently happening on our planet,” explained senior author Mauricio Santillana. “But until now, hypotheses about how these phenomena relate to each other have been sparse.”
Brownstein said that the research highlights an urgent need to gain a better understanding of how our changing environment is interconnected with infectious disease and medicine.
The study is published in the journal Nature Climate Change.
Jet stream air flow traffic jams can trigger severe weather
When a jet stream causes large masses of air to stall out and linger, this process is known as atmospheric blocking. Researchers have found that blocked atmospheric circulations closely resemble traffic jams.
Atmospheric blocking can cause weather patterns to stall over the same regions, triggering floods, heat waves, droughts, and other severe weather events.
The exact cause of blocking is not very well understood, and neither is the influence that climate change may have on the frequency of blocking events. This uncertainty makes it difficult to accurately predict weather.
Noboru Nakamura is a researcher in Atmospheric and Environmental Fluid Dynamics. He teamed up with Clare Huang to develop a new system for interpreting the nature of atmospheric blocking.
To understand the processes underlying blocking, the experts combined the use of mathematical theory with a metric for assessing jet streams which they had previously developed.
The study revealed that jet streams which become blocked appear to be very similar to traffic jams, in terms of flow and density of vehicles.
In light traffic, most cars travel at around the same speed which makes the traffic flow proportionate to traffic density. When traffic becomes congested, the flow of traffic is slowed down, which is precisely what happens to air flow in atmospheric blocking.
Blocking slows down eastward winds, and a highly meandering jet stream can also steer extreme weather. In 2012, atmospheric blocking is what drove Superstorm Sandy onto an unexpected path toward New Jersey.
The authors found that climate change has the potential to alter the frequency of atmospheric blocking by changing the risk for a jet stream to hit capacity and become overcrowded.
The study is published by the American Association for the Advancement of Science (AAAS) in the journal Science.
Chicxulub asteroid strike drove temperatures up for 100,000 years
A team of researchers may have finally settled a long-standing debate on what temperatures were like after the Chicxulub asteroid event 65 million years ago. The experts found that the asteroid strike triggered global warming and drove temperatures up by five degrees Celsius, which persisted for around 100,000 years.
After the asteroid crashed into the Earth, systems were disturbed at a rate much faster than the shift that is currently being caused by human activities. Understanding the extreme impact of the event can give scientists insight into the environmental changes that are happening now.
There has been much debate over what happened in the aftermath of the Chicxulub asteroid strike. Some scientists support the theory that global cooling set in after soot in the atmosphere blocked out the sun, while others believe that carbon dioxide released upon impact led to global warming.
A team of researchers led by Ken MacLeod set out to determine how temperatures were affected after the asteroid strike by analyzing the well-preserved remains of fish teeth, scales, and bone from a site in Tunisia. The samples have oxygen isotopic signatures that can reveal the temperature at the time the animals were still living.
The experts examined fossils from sediments that range from the time leading up to the Chicxulub impact until long after the event took place.
The investigation showed that global temperatures increased by about five degrees Celsius and persisted for roughly 100,000 years after the asteroid struck the Earth. The extent and duration of global warming identified in the study closely correlate with levels of carbon dioxide that were reported in other analyses of the Chicxulub event.
The study is published by the American Association for the Advancement of Science (AAAS) in the journal Science.
How long can the Trump admin ignore climate change science?
While the majority of the world’s governments are in agreement that human activities are at the core of climate change and that action must be taken to reduce emissions, the Trump administration has continued to ignore science.
Trump himself has famously called climate change “a hoax” and even taunted political opponents during the cold days of winter, claiming the northeast “could use some global warming.” Oddly, Trump’s own administration still released an official government report stating in no uncertain terms that human activity is driving climate change.
Now, according to a recent report from the Washington Post, an internal memo from last year showed the White House weighing its options of whether to simply “ignore” all climate change research, or to actually develop a “fact-based” approach.
It was an internal document written by Michael Catanzaro, the president’s special assistant for domestic energy and environmental policy at the time the memo was drafted.
The memo, according to the Washington Post, was presented to a staff of senior White House and agency officials in September and discussed having an official stance on climate change.
Catanzaro wrote wondering whether the Trump administration should “consider having a firm position on and a coherent, fact-based message about climate science — specifically, whether, and to what extent, anthropogenic emissions of greenhouse gases are affecting the climate system, and what level of concern that warrants.”
The options presented by Catanzaro included the possibility of a red and blue debate to show the inconsistencies and uncertainties of climate science, or the option to just ignore all climate science. None of the options involved emphasizing or “touting” climate study findings.
The administration didn’t take any formal position on climate change, but as Trump continues to push for coal and other fossil fuels as well confuse weather events as a means to disprove climate change, the unofficial position is clear.
Yet, despite the new administration’s attempts to largely ignore federal scientific findings, new reports and studies continue to be published that show the clear harmful effects of human activities on the world’s climate.
“The scientific evidence about accelerating effects of carbon dioxide and greenhouse gases in the atmosphere is so strong, and so prevalent, that it would be impossible to hush it up even if you wanted to,” Rush Holt, CEO of the American Association for the Advancement of Science told the Washington Post. “Coral deaths and glacier melting and sea-level rise, and all of these things are just so well documented and there’s just new evidence every day, whether it’s from USGS, or [the National Oceanic and Atmospheric Administration], or NASA, or Department of Energy, or various academic institutions. It just can’t be swept under the rug.”
Rice will lose nutritional value as carbon dioxide levels rise
When rice was grown under the atmospheric conditions that are expected in the second half of this century, iron, zinc, protein, and vitamins B1, B2, B5, and B9 were all reduced.
Study co-author Professor Kazuhiko Kobayashi is an expert on the impacts of air pollution on agriculture.
“Rice is not just a major source of calories, but also proteins and vitamins for many people in developing countries and for poorer communities within developed countries,” said Professor Kobayashi.
People in countries with the highest rice consumption and the lowest gross domestic product could face increasing rates of malnutrition as the nutritional value of rice and other low-cost foods decline.
However, not all types of rice responded to the experiential conditions in the same way, which means there is a chance that scientists could identify varieties of rice that maintain their nutritional value regardless of CO2 levels.
The rice was grown at research sites in China and Japan, where researchers built 55-foot-wide plastic pipes elevated about a foot above the tops of plants within standard rice fields. Wind speed and direction were measured by a network of sensors and monitors to control how much carbon dioxide was released out of the pipes, which is a technique known as Free-Air Carbon dioxide Enrichment (FACE).
“I first started using this technique in 1998, because we knew that plants raised in a plastic or glass house do not grow the same as plants in normal, open field conditions,” explained Professor Kobayashi.
“This technique allows us to test the effects of higher carbon dioxide concentrations on plants growing in the same conditions that farmers really will grow them some decades later in this century.”
There were some challenges to overcome, such as the interference of wild animals.
“At our first field site, we learned we have to keep all of the pipes and tubes above the ground because raccoons kept chewing through everything and jeopardized the experiment,” said Professor Kobayashi.
Researchers analyzed a total of 18 different varieties of rice to look for protein, iron, and zinc levels, while nine varieties of rice grown in China were used for testing levels of vitamins B1, B2, B5, and B9.
Six hundred million people in regions such as Bangladesh, Cambodia, Indonesia, Lao People’s Democratic Republic, Myanmar, Vietnam, and Madagascar get at least 50 percent of their daily protein directly from rice.
The research is published in the journal Science Advances.
Forests and tree-dwelling birds died when dinosaurs vanished
A team of scientists has revealed that dinosaurs were not the only casualty of the catastrophic asteroid event 66 million years ago. The experts have discovered that the world’s forests were also completely destroyed, which caused the extinction of tree-dwelling birds.
Study co-author Regan Dunn is a paleontologist at the Field Museum in Chicago.
“Looking at the fossil record, at plants and birds, there are multiple lines of evidence suggesting that the forest canopies collapsed,” said Dunn.
Lead author Daniel Field explained that the team used a combination of techniques for the investigation.
“We concluded that the temporary elimination of forests in the aftermath of the asteroid impact explains why arboreal birds failed to survive across this extinction event,” said Field. “The ancestors of modern arboreal birds did not move into the trees until forests had recovered from the extinction-causing asteroid.”
Study co-author Antoine Bercovici is a pollen expert at the Smithsonian Institution and the Denver Museum of Nature and Science, Bercovici analyzed microscopic fossils of pollen and spores to determine that the planet’s forests were destroyed.
“After a disaster like a forest fire or a volcanic eruption, the first plants to come back are the fastest colonizers – especially ferns,” said Dunn. This is due to fact that ferns do not sprout from seeds, but from small spores that are made up of just a single cell.
“Spores are minuscule, the size of a grain of pollen, so they’re easily dispersed. They get picked up by the wind and go further than seeds can, and all they need to grow is a wet spot.”
“The spores are tiny – you could fit four across a single strand of your hair. To see them, we take a sample of rock from the time frame just after the collision and dissolve it in acid. Then we purify it so that all that remains is the organic debris, like pollen, spores and little leaf bits, then we look at them under a microscope.”
Immediately after the asteroid collided with the Earth, the fossil record showed the charcoal remains of trees, and then, tons of fern spores.
“Our study examined the fossil record from New Zealand, Japan, Europe and North America, which showed there was a mass deforestation across the globe at the end of the Cretaceous period,” said Bercovici.
The researchers found that the only birds that survived were ground-dwellers. Their fossilized remains contained strong legs like modern ground birds such as kiwis and emus. Tree-dwelling birds have delicate legs that are designed for perching on branches, and they had no place left to live.
“Today, birds are the most diverse and globally widespread group of terrestrial vertebrate animals–there are nearly 11,000 living species,” said Field. “Only a handful of ancestral bird lineages succeeded in surviving the mass extinction event 66 million years ago, and all of today’s amazing living bird diversity can be traced to these ancient survivors.”
Dunn pointed out that fossil plants are critical in reconstructing the history of life on earth.
“Plants are everything, plants are the context in which all terrestrial life evolves and survives. They’re primary producers, they make energy available to all life forms by capturing it from the sun–we can’t do that.”
Dunn also emphasized that the loss of life resulting from the mass extinction 66 million years ago is relevant today.
“The end-Cretaceous event is the fifth mass extinction – we’re in the sixth,” said Dunn. “It’s important for us to understand what happens when you destroy an ecosystem, like with deforestation and climate change–so we can know how our actions will affect what comes after us.”
The study is published in the journal Current Biology.
image Credit: Regan Dunn, The Field Museum
Conservation efforts have proven successful against great odds
When researchers study population declines, they often cite the vital importance of conservation, management, and restoration efforts.
But sometimes it can be difficult to grasp the full weight of just how many species are threatened, endangered, and even facing extinction when studies focus on one species or habitat at a time.
According to the International Union for the Conservation of Nature (IUCN), nearly 80,000 plants and animals are endangered and are part of the IUCN’s Red List.
Of those 80,000, almost a third could soon face extinction with 41 percent of amphibians, 34 percent of conifer trees, and 25 percent of mammals in jeopardy, according to a recent Agence France-Presse (AFP) article.
These numbers are grim, but there are quite a few success stories that could serve as inspiration to help reverse further population declines.
Conservationists have brought quite a few species back from the brink, thanks to captive breeding, tracking populations, and restoring habitats.
The Mauritius kestrel, a falcon whose species was all but wiped in 1974, is now an example of one of the most successful bird restoration projects in history. Captive breeding and predator control has increased Mauritius kestrel numbers from four to four hundred.
Another example of successful conservation can be found on Madagascar with the greater bamboo lemur. The species is still seriously threatened, but a national park was erected around the lemurs’ natural habitat, protecting it from future declines.
Conservationists can work to raise awareness of endangered or threatened species among a community, or work with policymakers and national leaders to reduce human activities near reduced habitats.
“The sixth mass extinction is happening now,” said Craig Hilton-Taylor, the head of the Red List, told the AFP. “But these conservation achievements highlight that there is still reason to be hopeful for the future of our planet, and that conservation does work.”
When land first rose above water, it transformed Earth’s climate
The Earth may have undergone a drastic transformation 2.4 billion years ago with a rapid rise of land above the ocean, according to a new study.
Researchers from the University of Oregon examined isotopes in shale samples from all over the world and found nearly imperceptible traces of rainwater.
This points to the possibility that during Earth’s early years, newly exposed land underwent dramatic weathering that would have triggered changes in the Earth’s geographic makeup, climate, and even life.
The study was published in the journal Nature and the results show that land weathering may have occurred as early as 3.5 billion years ago.
The researchers analyzed three oxygen isotopes, oxygen 16, the rare but stable 17 and 18, in 278 shale samples taken from every continent and spanning 3.7 billion years.
After identifying changes in the ratios of the isotopes in the shale, the researchers were able to better establish when newly exposed crust, after rising above sea level, was exposed to chemical and physical weathering such as rainfall.
The results also coincide with previous hypotheses about when the Earth’s first supercontinent was formed with mountain ranges and plateaus.
“Crust needs to be thick to stick out of water,” said Ilya Bindeman, the study’s lead author. “The thickness depends on its amount and also on thermoregulation and the viscosity of the mantle. When the Earth was hot and the mantle was soft, large, tall mountains could not be supported. Our data indicate that this changed exponentially 2.4 billion years ago. The cooler mantle was able to support large swaths of land above sea level.”
The surface temperature during this time was likely hotter by several tens of degrees that what we see today according to the researchers.
Not only does the study provide a possible timeframe for the development of major land formations and weathering, but the rise of land above sea-level at this time coincides with the transition from the Archean Eon to the Proterozoic Eon when algae and plants first emerged.
The stepwise changes in triple-isotopes of oxygen in the shale show that land emerged in a stepwise pattern between 1.1 and 3.5 billion years ago and 2.4 billion years ago, the land began to absorb carbon dioxide.
The study’s results show how the world’s first landmasses emerged and when chemical weathering took place, changing the world’s climate. The newly formed landscapes would have even led to changes in the reflection of solar radiation.
“What we speculate is that once large continents emerged, light would be reflected back into space and initiate runaway glaciation,” said Bindeman. “Earth would have seen its first snowfall.”
Japan may dump 1 million tons of radioactive water into Pacific
The Japanese government is searching for a way to dispose of over one million tons of radioactive water, and one proposed solution is to dump the contaminated water into the ocean.
At the Fukushima No. 1 nuclear power plant, storage space for tanks that hold contaminated water and other materials is approaching the limit. The storage tanks have a capacity of about 1.13 million tons, and 1.07 million tons of that capacity is currently in use. An estimated 80 percent of storage space is dedicated to holding tritium water.
When water enters the abandoned nuclear plant, it becomes contaminated at a rate of around 160 tons per day. Many of the radioactive materials are removed by treating the water, but a radioactive isotope of hydrogen called tritium persists.
Forests have been leveled to accommodate the storage of tritium water tanks. Although the space cleared to hold the tanks has now grown to about 230,000 square meters, the storage capacity is still running out.
Government researchers reported in June 2016 that releasing tritium water into the ocean would be the fastest and cheapest of the five disposal methods they identified. Other ideas were to release the radioactive water by evaporation, store it underground, release the water after electrolysis, or to inject it into geological layers.
The industry ministry also established an expert committee to look into safety measures. A year and a half has now passed since the first meeting of the committee, but a solution has still not been announced.
Currently, the tritium water produced at Fukushima is ten times the national limit of contamination to be dumped into the ocean. The water may be able to meet these standards upon further dilution.
By Chrissy Sexton, Earth.com Staff Writer