A study found brief exposure to diesel exhaust fumes altered functional connectivity in a human brain in ways researchers suggest could affect cognitive function..Depositphotos
Researchers in Canada have, for the first time ever, demonstrated how acute exposure to traffic pollution can immediately impair human brain function, offering unique evidence of the connection between air quality and cognition. Healthy adults were exposed to diesel fumes before having their brain activity imaged in a fMRI machine.
Air pollution in urban environments has long been associated with poor cardiovascular, respiratory and brain health. But connecting the dots between air quality and human health has been challenging for researchers. It’s difficult to accurately quantify a person’s exposure to air pollution beyond associating rates of certain diseases in geographical areas of high pollution.
Plenty of cell and animal studies can demonstrate how air pollution affects organisms. But as we know, there can often be a huge chasm between the effects of toxins on a mouse in a lab and chronic exposure to a human in the real world.
So perhaps the final missing piece in the puzzle for researchers has been direct human exposure studies. Of course, it’s not exactly ethical to expose volunteers to high levels of toxic fumes just to watch what happens, so these kinds of experiments, unsurprisingly, have been lacking.
This new research used a model of human exposure to diesel exhaust fumes developed over a decade ago. The technique delivers controlled and diluted concentrations of diesel exhaust particulate matter to human subjects at levels deemed to be representative of real-world exposure but also proven to be safe. In a lab setting, 25 healthy adults were exposed to either diesel exhaust, or filtered air for two hours and had their brain activity measured using fMRI before and after each exposure.
The main focus of the study was on the impact of this kind of traffic-associated air pollution on what is known as the default mode network (DMN). This is a set of inter-connected cortical brain regions that play a crucial role in cognition, memory and emotion.
The findings revealed brief exposure to diesel exhaust caused a decrease in DMN activity, essentially yielding a drop in functional connectivity between different brain regions, compared to what was seen when subjects were exposed to filtered air. Jodie Gawryluk, first author on the study, said these kinds of DMN alterations have been linked to depression and cognitive decline.
“We know that altered functional connectivity in the DMN has been associated with reduced cognitive performance and symptoms of depression, so it’s concerning to see traffic pollution interrupting these same networks,” said Gawryluk. “While more research is needed to fully understand the functional impacts of these changes, it’s possible that they may impair people’s thinking or ability to work.”
Alone, these new findings are not particularly meaningful. No evaluations were performed in the study to suggest the observed DMN changes impacted cognition. But alongside a growing body of epidemiological and preclinical studies linking air pollution with a number of neurodegenerative diseases, these findings may be much more significant. They effectively demonstrate the acute effects of air pollution on the human brain in a way never before shown.
According to senior author on the study Chris Carlsten, it is unclear what long-term effects this kind of pollution exposure will have on a human brain. On the positive side of things the researchers did seen DMN brain activity return to normal relatively soon after the diesel fume exposure. So Carlsten is only able to hypothesize what the impact of more chronic, continuous exposure could be.
“People may want to think twice the next time they’re stuck in traffic with the windows rolled down,” said Carlsten. “It’s important to ensure that your car’s air filter is in good working order, and if you’re walking or biking down a busy street, consider diverting to a less busy route.”
Rich has written for a number of online and print publications over the last decade while also acting as film critic for several radio broadcasters and podcasts. His interests focus on psychedelic science, new media, and science oddities. Rich completed his Masters degree in the Arts back in 2013 before joining New Atlas in 2016.
A new study in Nature Sustainability incorporates the damages that climate change does to healthy ecosystems into standard climate-economics models. The key finding in the study by Bernardo Bastien-Olvera and Frances Moore from the University of California at Davis:
The models have been underestimating the cost of climate damages to society by a factor of more than five. Their study concludes that the most cost-effective emissions pathway results in just 1.5 degrees Celsius (2.7 degrees Fahrenheit) additional global warming by 2100, consistent with the “aspirational” objective of the 2015 Paris Climate Agreement.
Models that combine climate science and economics, called “integrated assessment models” (IAMs), are critical tools in developing and implementing climate policies and regulations.
In 2010, an Obama administration governmental interagency working group used IAMs to establish the social cost of carbon – the first federal estimates of climate damage costs caused by carbon pollution. That number guides federal agencies required to consider the costs and benefits of proposed regulations.
Economic models of climate have long been criticized by those convinced they underestimate the costs of climate damages, in some cases to a degree that climate scientists consider absurd. Given the importance of the social cost of carbon to federal rulemaking, some critics have complained that the Trump EPA used what they see as creative accounting to slash the government’s estimate of the number. In one of his inauguration day Executive Orders, President Biden established a new Interagency Working Group to re-evaluate the social cost of all greenhouse gases.
IAMs often have long been criticized by those convinced they underestimate the costs of climate damages, in some cases to a degree that climate scientists consider absurd. Perhaps the most prominent IAM is the Dynamic Integrated Climate-Economy (DICE) model, for which its creator, William Nordhaus, was awarded the 2018 Nobel Prize in Economic Sciences.
Judging by DICE, the economically optimal carbon emissions pathway – that is, the pathway considered most cost-effective – would lead to a warming increase of more than 3°C (5.4°F) from pre-industrial temperatures by 2100 (under a 3% discount rate). IPCC has reported that reaching this level of further warming could likely result in severe consequences, including substantial species extinctions and very high risks of food supply instabilities.
In their Nature Sustainability study, the UC Davis researchers find that when natural capital is incorporated into the models, the emissions pathway that yields the best outcome for the global economy is more consistent with the dangerous risks posed by continued global warming described in the published climate science literature.
Accounting for climate change degrading of natural capital
Natural capital includes elements of nature that produce value to people either directly or indirectly. “DICE models economic production as a function of generic capital and labor,” Moore explained via email. “If instead you think natural capital plays some distinct role in economic production, and that climate change will disproportionately affect natural capital, then the economic implications are much larger than if you just roll everything together and allow damage to affect output.”
Bastien-Olvera offered an analogy to explain the incorporation of natural capital into the models: “The standard approach looks at how climate change is damaging ‘the fruit of the tree’ (market goods); we are looking at how climate change is damaging the ‘tree’ itself (natural capital).” In an adaptation of DICE they call “GreenDICE,” the authors incorporated climate impacts on natural capital via three pathways:
The first pathway accounts for the direct influence of natural capital on market goods. Some industries like timber, agriculture, and fisheries are heavily dependent on natural capital, but all goods produced in the economy rely on these natural resources to some degree.
According to GreenDICE, this pathway alone more than doubles the model’s central estimate of the social cost of carbon in 2020 from $28 per ton in the standard DICE model to $72 per ton, and the new economically optimal pathway would have society limit global warming to 2.2°C (4°F) above pre-industrial temperatures by 2100.
The second pathway incorporates ecosystem services that don’t directly feed into market goods. Examples are the flood protection provided by a healthy mangrove forest, or the recreational benefits provided by natural places.
In the study, this second pathway nearly doubles the social cost of carbon once again, to $133 per ton in 2020, and it lowers the most cost-effective pathway to 1.8°C (3.2°F) by 2100. Finally, the third pathway includes non-use values, which incorporate the value people place on species or natural places, regardless of any good they produce. The most difficult to quantify, this pathway could be measured, for instance, by asking people how much they would be willing to pay to save one of these species from extinction.
In GreenDICE, non-use values increase the social cost of carbon to $160 per ton of carbon dioxide in 2020 (rising to about $300 in 2050 and $670 per ton in 2100) and limit global warming to about 1.5°C (2.8°F) by 2100 in the new economically optimal emissions pathway. (Note for economics wonks – the model runs used a 1.5% pure rate of time preference.)
Climate economics findings increasingly reinforce Paris targets
It may come as no surprise that destabilizing Earth’s climate would be a costly proposition, but key IAMs have suggested otherwise. Based on the new Nature Sustainability study, the models have been missing the substantial value of natural capital associated with healthy ecosystems that are being degraded by climate change.
Columbia University economist Noah Kaufman, not involved in the study, noted via email that as long as federal agencies use the social cost of carbon in IAMs for rulemaking cost-benefit analyses, efforts like GreenDICE are important to improving those estimates. According to Kaufman, many papers (including one he authored a decade ago) have tried to improve IAMs by following a similar recipe: “start with DICE => find an important problem => improve the methodology => produce a (usually much higher) social cost of carbon.”
For example, several other papers published in recent years, including one authored by Moore, have suggested that, because they neglect ways that climate change will slow economic growth, IAMs may also be significantly underestimating climate damage costs. Poorer countries – often located in already-hot climates near the equator, with economies relying most heavily on natural capital, and lacking resources to adapt to climate change – are the most vulnerable to its damages, despite their being the least responsible for the carbon pollution causing the climate crisis.
Another recent study in Nature Climate Change updated the climate science and economics assumptions in DICE and similarly concluded that the most cost-effective emissions pathway would limit global warming to less than 2°C (3.6°F) by 2100, without even including the value of natural capital. Asked about that paper, Bastien-Olvera noted, “In my view, the fact that these two studies get to similar policy conclusions using two very different approaches definitely indicates the urgency of cutting emissions.”
Recent economics and climate science research findings consistently support more aggressive carbon emissions efforts consistent with the Paris climate targets.
Wesleyan University economist Gary Yohe, also not involved in the study, agreed that the new Nature Sustainability study “supports growing calls for aggressive near-term mitigation.” Yohe said the paper “provides added support to the notion that climate risks to natural capital are important considerations, especially in calibrating the climate risk impacts of all sorts of regulations like CAFE standards.”
But Yohe said he believes that considering the risks to unique and threatened systems at higher temperatures makes a more persuasive case for climate policy than just attempting to assess their economic impacts. In a recent Nature Climate Change paper, Kaufman and colleagues similarly suggested that policymakers should select a net-zero emissions target informed by the best available science and economics, and then use models to set a carbon price that would achieve those goals.
Their study estimated that to reach net-zero carbon pollution by 2050, the U.S. should set a carbon price of about $50 per ton in 2025, rising to $100 per ton by 2030. However climate damages are evaluated, whether through a more complete economic accounting of adverse impacts or via risk-based assessments of physical threats to ecological and human systems, recent economics and climate science research findings consistently support more aggressive carbon emissions efforts consistent with the Paris climate targets.
Twenty-two kilometers of salt water separates the island of Jersey from France. But it didn’t used to. Photo by Mauritius images GmbH/Alamy Stock Photo
It wasn’t long after Henry David Inglis arrived on the island of Jersey, just northwest of France, that he heard the old story. Locals eagerly told the 19th-century Scottish travel writer how, in a bygone age, their island was much more substantial, and that folks used to walk to the French coast. The only hurdle to their journey was a river—one easily crossed using a short bridge.
“Pah!” Inglis presumably scoffed as he looked out across 22 kilometers of shimmering blue sea—because he went on to write in his 1832 book about the region that this was “an assertion too ridiculous to merit examination.” Another writer, Jean Poingdestre, around 150 years earlier, had been similarly unmoved by the tale. No one could have trod from Jersey to Normandy, he withered, “vnlesse it were before the Flood,” referring to the Old Testament cataclysm.
Yet, there had been a flood. A big one. Between roughly 15,000 and 5,000 years ago, massive flooding caused by melting glaciers raised sea levels around Europe. That flooding is what eventually turned Jersey into an island. Rather than being a ridiculous claim not worthy of examination, perhaps the old story was true—a whisper from ancestors who really did walk through now-vanished lands. A whisper that has echoed across millennia.
That’s exactly what geologist Patrick Nunn and historian Margaret Cook at the University of the Sunshine Coast in Australia have proposed in a recent paper. In their work, the pair describe colorful legends from northern Europe and Australia that depict rising waters, peninsulas becoming islands, and receding coastlines during that period of deglaciation thousands of years ago. Some of these stories, the researchers say, capture historical sea level rise that actually happened—often several thousand years ago.
For scholars of oral history, that makes them geomyths. “The first time I read an Aboriginal story from Australia that seemed to recall the rise of sea levels after the last ice age, I thought, No, I don’t think this is correct,” says Nunn. “But then I read another story that recalled the same thing.”
Nunn has since gathered 32 groups of stories from Indigenous communities around the coast of Australia—a continent nearly as large as Europe—that seem to refer to geological changes along shorelines. Take the legend of Garnguur, told by the Lardil people, also known as Kunhanaamendaa, in the Wellesley Islands, off northern Australia. It describes a seagull woman, Garnguur, who cut the islands off from the mainland by dragging a giant raft, or walpa, back and forth across a peninsula.
In some versions of the story, this is punishment for her brother, Crane, who failed to look after her child when asked. Nunn and Cook argue that the narrative can be taken as a memory of how, no more than 10,000 years ago, melting glaciers caused the Wellesley Islands to be cut off from the mainland. Interestingly, there is a large underwater trench between two of the Wellesley Islands—perhaps a feature of the seabed that prompted the image of Garnguur plowing her raft into the earth, the researchers suggest in their paper.
Separately, other Indigenous groups in South Australia, such as the Ngarrindjeri and Ramindjeri, tell of a period when Kangaroo Island was once connected to the mainland. Some say it got cut off by a big storm, while others describe a line of partially submerged boulders that once allowed people to cross to the island.
For Jo Brendryen, a paleoclimatologist at the University of Bergen in Norway who has studied the effects of deglaciation in Europe following the end of the last ice age, the idea that traditional oral histories preserve real accounts of sea level rise is perfectly plausible.
During the last ice age, he says, the sudden melting of ice sheets induced catastrophic events known as meltwater pulses, which caused sudden and extreme sea level rise. Along some coastlines in Europe, the ocean may have risen as much as 10 meters in just 200 years. At such a pace, it would have been noticeable to people across just a few human generations.
“These stories are anecdotes, but enough anecdotes makes for data,” Brendryen explains. “By systematically collecting these kinds of memories or stories, I think you can learn something.” Beyond capturing historical events, geomyths offer a glimpse into the inner lives of those who were there, says Tim Burbery, an expert on geomyths at Marshall University in West Virginia, who was not involved in the research: “These are stories based in trauma, based in catastrophe.”
That, he suggests, is why it may have made sense for successive generations to pass on tales of geological upheaval. Ancient societies may have sought to broadcast their warning: beware, these things can happen! “They would mythologize it,” Burbery adds. “They would use the language of legend, and within that there could be some real data.”
Today, many people report a sense of eco-anxiety because of climate change and its effects, including sea level rise. Nunn points out that our contemporary situation differs in some ways from ancient predicaments—there are many more humans on the planet and huge, densely populated coastal cities, for example. And unlike historical periods of deglaciation, we are today both the agents and victims of rapid environmental change.
But vulnerability to climatic shifts allows us to feel an affinity toward our forebears. And the old stories still have things to teach us. As Nunn says, “the fact that our ancestors have survived those periods gives us hope that we can survive this.”
The Earth’s climate has been quite stable over the past 11,000 years, playing an important role in the development of human civilisation. Prior to that, the Earth experienced an ice age lasting for tens of thousands of years. The past million years of the Earth’s history has been characterised by a series of ice ages broken up by relatively short periods of warmer temperatures.
These ice ages are triggered and ended by slow changes in the Earth’s orbit. But changing atmospheric concentrations of CO2 also plays a key role in driving both cooling during the onset of ice ages and warming at their end. The global average temperature was around 4C cooler during the last ice age than it is today. There is a real risk that, if emissions continue to rise, the world warms more this century than it did between the middle of the last ice age 20,000 years ago and today.
In this explainer, Carbon Brief explores how the last ice age provides strong evidence of the role CO2 plays as a “control knob” for the Earth’s climate. It also acts as a cautionary tale of how the climate can experience large changes from relatively small outside “forcings”.
The Earth has experienced a number of periods over the past million years in which large continental ice sheets have covered much of the northern hemisphere. These ice ages are associated with a large drop in global temperatures – 4C or more below today’s levels – with much larger changes over land and in the high latitudes.
These ice ages are punctuated by “interglacial” periods where temperatures rise to around current levels. The most recent ice age occurred between 120,000 and 11,500 years ago, while the current interglacial period – the Holocene – is expected to last for additional tens of thousands of years (and human activity may inadvertently delay the start of the next ice age even further).
Ice-age cycles are primarily driven by periodic changes in the Earth’s orbit. Three distinct orbital cycles – called Milankovitch cycles after their discoverer, Serbian scientist Dr Milutin Milankovitch – interact to change the distribution of incoming solar energy in ways that can dramatically affect the Earth’s climate.
Precession – a 26,000-year shift in the orientation of Earth’s axis of rotation that affects how much summer sun is received at high latitudes (and shifting how much reaches the north vs south).
Obliquity – a 41,000-year change in the tilt of the Earth’s axis relative to the sun that changes how much sun is received during a year at the poles versus the equator.
Eccentricity – a 100,000-400,000 change in the shape of the Earth’s orbit around the sun that alters the length of the seasons and affects the importance of precession.
These three cycles overlap in different ways over time given their different periods, which means that ice ages do not always have the same duration. None of these cycles substantially changes the total amount of energy reaching the Earth from the sun; rather, they mostly act to change the distribution of the sun’s energy across the surface of the Earth.
When these cycles cause the northern latitudes to get less sun in the summer, it allows ice sheets to begin to expand. These ice sheets in turn reflect more incoming sunlight back to space, resulting in a “positive feedback” that drives additional regional cooling.
The northern latitudes matter much more than the southern latitudes – at least over the past few million years – as it contains more land area (which can more easily become ice-covered than the oceans) and because the Antarctic has remained covered in ice…..To be continued
A comparison of a test area treated with PrairieFood's micro-carbon additive on the left with ... [+]PrairieFood.com
This March, I introduced the term “Nature-Enhancing Solution” to describe technologies based on natural processes that have been capturing and productively using atmospheric carbon for hundreds of millions of years in one of the three interlocking “gears” – the terrestrial, marine, and geological cycles – that make up the full carbon cycle.
My Pi Day article was all about the smallest gear, the terrestrial cycle. One entrepreneur whose work I have featured in this column before – Robert Herrington, co-founder of Kansas-based PrairieFood – believes he and his team have discovered a Nature-Enhancing Solution to draw down excess atmospheric carbon dioxide while simultaneously restoring health to our planet and improving the quality of our food.
Let me underscore that last sentence because its impact is profound: Herrington believes he has found a way to solve the climate crisis while making our land richer and our food healthier. PrairieFood’s reactors pull in biological waste – manure, the slag left over after beer is brewed, and even treated sewage. This waste contains carbons in long, complex chains, which are difficult for soil-based organisms to consume.
The reactors shred those long carbon strands in a matter of seconds to create short carbon strands that are easily digestible by soil organisms. Those short strands, suspended in water, can then be sprayed onto fields using conventional equipment. The reason we put old coffee grounds and banana peels and fallen leaves into a compost pile is to take the long chains of carbon from biological sources and let nature (fungi, insects, worms, etc.) break them down into the black soil that we shovel into our gardens.
This natural process takes many seasons and yields a relatively small volume of short-carbon strands. PrairieFood’s Nature-Enhancing Solution makes the composting process much more efficient in time and volume. In other words, Herrington and his team have invented a device that acts like a composting time machine.When PrairieFood “slurry” is applied to agricultural fields, the organisms within the soil think they have stumbled upon an all-you-can-eat buffet.
They consume the carbon and provide “services” to the crops (e.g., “fixing” nitrogen – taking nitrogen out of the air and providing it to the plants). As the organisms give the plants more of what they need, the plants flourish. In return, the plants photosynthesize more actively – pulling in more carbon dioxide and changing it to sugars, some of which they give back to the soil organisms through their root systems.
This has the same sort of effect agriculturally as someone bringing more food and drink to a party. The soil-borne organisms love the extra food, and their populations swell to eat it all up. This starts a virtuous cycle by which the organisms help the plants, and the plants help the organisms, on and on.
The virtuous cycle creates a truly profound “multiplier effect” by which a little PrairieFood can have enormous impacts on the concentration of what is known as “Soil Organic Matter” (SOM) of which “Soil Organic Carbon” (SOC) forms a large part.
PrairieFood’s Amazing Results
Herrington and his co-founder, Dr. Griffin Roberts, have three years’ worth of field trials and commercial application of PrairieFood onto agricultural acreage. After some trial and error, they have found that applying 40 gallons of PrairieFood on an acre of cropland is sufficient to raise the amount of SOM by one percentage point over a single season.
That is about ten times the rate at which SOM is usually increased using organic fertilizers and other regenerative farming techniques. (Using conventional farming techniques actually decreases SOM concentrations – essentially desertifying croplands… more about that in an upcoming article.)
I started doing some back-of-the-envelope calculations about this multiplier effect and literally had to double and triple check my work. Dr. Roberts and I talked through the calculations and indeed, PrairieFood’s multiplier effect is off the charts – the addition of a very small amount of carbon (in the form of PrairieFood slurry) ends up generating a multiplier effect in the hundreds of thousands!
A comparison of seedling alfalfa plants. The plant on the left was grown with 40 gallons per acre of … [+] PrairieFood slurry; the plant on the right was grown with conventional fertilizer. Note the different in size of not only the above-ground part of the plants, but also the root system.
The reason I was so surprised is that I’m used to thinking about multiplier effects in the world of economics and finance that are in the single digits at most. But when dealing with microscopic organisms, there can be trillions of microbes in a scoopful of soil. As such, the number of microbes in an acre-foot of agricultural land (an acre-foot is the volume of soil in an acre to a depth of 1 foot) is phenomenally high. It is this astronomical number of organisms in the soil – all of which increase population exponentially given enough food – that creates the astounding multiplier effect.
Not all fields respond [with] such dramatic effect, [and] we have seen a range of responses. At times we have witnessed biological community shifts. This happens when nutrient food sources change in microbial populations. The shifts we see typically include [a] balancing of bacterial and [fungal] populations (most [agricultural] fields are bacterial dominated), and/or a rise in [the populations of small organisms] such as nematodes and Protozoa, etc. These higher [small organism population] levels…consume bacterial and [fungal] populations [and] play another significant role in nutrient cycling, both carbon and nitrogen…
“We have found where [farmers] that have applied manure and/or reduced [the practice of tilling, or turning up the soil] in the past, typically see the highest increase right away. We believe [that in these cases] the soil is primed for biological activity but is still stagnant/dormant, so when PrairieFood is applied, the nutrient cycling gets turned on right away, specifically in building SOM. Other fields which may have been…heavily reliant on [synthetic] mineral fertilizer, have a bit of adjusting at first.”
A Solution to the Climate Crisis
Herrington and Roberts have pulled together a thought experiment to illustrate the amazing potential of increasing SOM by a relatively small amount. “What if,” they ask “20% of agricultural land in our home state of Kansas could increase its SOM by one percentage point each year for 10 years?”
The answer to this question is amazing and offers great hope to the human civilization home team. An increase of SOM means a decrease in atmospheric CO2 levels – PrairieFood is enhancing the normal terrestrial carbon cycle. The increases posited would result in the draw-down of nearly 4 Gigatons of carbon!Widening the scope to a global level, the same increase in SOM in the 12.5 billion acres of land now used for agriculture would result in the draw-down of over 180 Gigatons of carbon.
For the average net addition to atmospheric carbon stores and the sources of change between 2009 and … [+] 2018, look at the graphic on the right. The red bar at the far right of the graph is the amount of carbon that was forced into the atmosphere in excess of what nature could absorb. 0.4 Gigatons on average.
To put this figure in context, according to a study done by the Earth System Science Data team at German-based Copernicus Publications, the average net increase in atmospheric carbon levels from 2009-2018 was 0.4 Gigatons per year. 180 Gigatons of atmospheric carbon drawdown would, in other words, remove 450 years’ worth of excess atmospheric carbon dioxide – enough to bring us back to the pre-Industrial Revolution average of 250 parts per million (and then some).
If saving civilization from burning up in a furnace of its own making was not enough, applications of PrairieFood slurry to fields creates a lot of other benefits as well.
The PrairieFood-driven SOM increase is important in part because carbon-rich soil stores so much more water than carbon-poor soil does. This will make agricultural regions less dependent on irrigation and much more resilient to flood-producing downpours; it will also give someplace for water absorbed from increasing sea levels to go beside someone’s condo. This is such an important topic that I will take it up in a separate article.
Turning to the benefits to human health, over the last 70 years, there has been a marked trend for vegetables to become less nutritious. The only way that vegetables can become more nutritious is to have healthier soil, so increasing soil health may tie directly to better human health for anyone who eats vegetables or who eats animals that eat vegetables.
I have a lot more to say about the work PrairieFood is doing, so will continue in an upcoming article. For those who want to learn more about this homespun start-up with a mission to do nothing less than save the planet, PrairieFood is sponsoring a conference on November 14-15 in beautiful Pratt, Kansas. I attended last year and credit a quantum shift in my thinking about multiple issues facing humanity—climate change, biodiversity collapse, water management, agricultural productivity, and human health—to my conversation with farmers and ranchers at that event.
Herrington and Roberts know, as I know, that the Goldilocks environmental conditions that have allowed humans to build complex societies teeter on a knife’s edge. Our carbon emissions are pushing us over that edge and threatening the stability of our civilization, which is literally built on agricultural advances. PrairieFood offers a way to right that balance and pull us back from the edge.
While rivers and reservoirs run dangerously low in Europe, there is catastrophic flooding in Pakistan and the US. Whether it’s a drought or a deluge, being able to accurately forecast rain is important to protect lives and manage water safely.
That has become more difficult in recent decades. Climate change and deforestation have warped Earth’s freshwater cycle, shifting rainfall patterns towards extreme events like severe droughts and downpours. Catastrophic floods have been on the rise globally in the last 50 years and incidences of flash flooding, when torrential rain falls in a very short period, have increased, particularly in tropical countries where high temperatures have made thunderstorms more common.
Developed countries like the UK have invested in satellites and radars for more accurate weather forecasting. These high-tech systems are particularly effective in temperate climates where rainfall typically occurs over several kilometres and moves in wide bands known as weather fronts. Measurements of rainfall over distances of 5 km or greater, which satellites and radars are capable of, are often sufficient for forecasting rain at this scale.
In tropical countries, where climate change is expected to have a far greater impact, systems that can forecast rain at distances of less than a kilometre are needed. This is because of something called convectional rainfall, which is common in the tropics. Convectional rainfall occurs when heated air rises upwards along with water vapour, which condenses to form clouds at a high altitude. These clouds are not carried away by the wind, and so rain falls in the same place it originated.
Systems capable of forecasting convectional rainfall would help authorities give advance warning, preventing deaths and flood damage. They could also help people manage this rainwater to benefit farms, with efficient drainage and irrigation measures.
Most tropical countries fall within low or middle income bands. Forecasting rain over distances smaller than a kilometre is expensive – weather satellites are often not feasible. Dense vegetation and hilly terrain, also common in tropical regions, can profoundly shape local weather by causing humid air to rise and condense, making conventional weather forecasting even trickier. To solve these problems, we set out to develop a cheap way of providing street-by-street forecasting.
AI-based tropical rainfall forecasting
Rainfall is the result of complex interactions between different components of the atmosphere such as temperature, humidity, pressure and wind speed which can be easily measured by sensors. We investigated whether artificial intelligence could use this information to compile a rainfall forecast in northern Malaysia.The forecasting system we developed is essentially an intelligent computer programme that can predict whether it will rain, how intense that rain will be and how long it will last at any location with greater than 90% accuracy at least 96 hours in advance.
We tested its forecasting accuracy against past weather conditions which preceded rain falling. If this algorithm included data from sensors measuring the depth and flow rate of rivers, it could predict whether rain might cause flooding, and if so, when and for how long.The devices used to measure weather conditions can be connected to the internet to form a network that offers regional forecasting. Adding more devices to the network will improve the accuracy of the forecast, which is updated hourly.
Working with University of Malaysia Perlis, we have already created an online network of existing weather sensors that collects data for our algorithm to use. Most of these weather stations are separated by tens of kilometres – too far apart to provide detailed rain forecasting in most areas.But, as more sensors are added, the forecasting system will hopefully one day ensure that vulnerable communities can better prepare for extreme weather events, and build resilience to the rapidly changing climate.
Global climate change is not a future problem. Changes to Earth’s climate driven by increased human emissions of heat-trapping greenhouse gases are already having widespread effects on the environment: glaciers and ice sheets are shrinking, river and lake ice is breaking up earlier, plant and animal geographic ranges are shifting, and plants and trees are blooming sooner.
Effects that scientists had long predicted would result from global climate change are now occurring, such as sea ice loss, accelerated sea level rise, and longer, more intense heat waves.Some changes (such as droughts, wildfires, and extreme rainfall) are happening faster than scientists previously assessed. In fact, according to the Intergovernmental Panel on Climate Change (IPCC) — the United Nations body established to assess the science related to climate change — modern humans have never before seen the observed changes in our global climate, and some of these changes are irreversible over the next hundreds to thousands of years.
Scientists have high confidence that global temperatures will continue to rise for many decades, mainly due to greenhouse gases produced by human activities. The IPCC’s Sixth Assessment report, published in 2021, found that human emissions of heat-trapping gases have already warmed the climate by nearly 2 degrees Fahrenheit (1.1 degrees Celsius) since pre-Industrial times (starting in 1750). The global average temperature is expected to reach or exceed 1.5 degrees C (about 3 degrees F) within the next few decades. These changes will affect all regions of Earth.
What’s the difference between climate change and global warming?
The severity of effects caused by climate change will depend on the path of future human activities. More greenhouse gas emissions will lead to more climate extremes and widespread damaging effects across our planet. However, those future effects depend on the total amount of carbon dioxide we emit. So, if we can reduce emissions, we may avoid some of the worst effects.
Climate change is bringing different types of challenges to each region of the country. Some of the current and future impacts are summarized below. These findings are from the Third and Fourth National Climate Assessment Reports, released by the U.S. Global Change Research Program.
Northeast. Heat waves, heavy downpours, and sea level rise pose increasing challenges to many aspects of life in the Northeast. Infrastructure, agriculture, fisheries, and ecosystems will be increasingly compromised. Farmers can explore new crop options, but these adaptations are not cost- or risk-free. Moreover, adaptive capacity, which varies throughout the region, could be overwhelmed by a changing climate. Many states and cities are beginning to incorporate climate change into their planning.
Northwest. Changes in the timing of peak flows in rivers and streams are reducing water supplies and worsening competing demands for water. Sea level rise, erosion, flooding, risks to infrastructure, and increasing ocean acidity pose major threats. Increasing wildfire incidence and severity, heat waves, insect outbreaks, and tree diseases are causing widespread forest die-off.
Southeast. Sea level rise poses widespread and continuing threats to the region’s economy and environment. Extreme heat will affect health, energy, agriculture, and more. Decreased water availability will have economic and environmental impacts.
Midwest. Extreme heat, heavy downpours, and flooding will affect infrastructure, health, agriculture, forestry, transportation, air and water quality, and more. Climate change will also worsen a range of risks to the Great Lakes.
Southwest. Climate change has caused increased heat, drought, and insect outbreaks. In turn, these changes have made wildfires more numerous and severe. The warming climate has also caused a decline in water supplies, reduced agricultural yields, and triggered heat-related health impacts in cities. In coastal areas, flooding and erosion are additional concerns.