However, what was a stunning vista in years past is now marred by dead trees virtually everywhere you look. Beyond the aesthetic impacts it also raises the question of whether these mountainsides and valleys are tinderboxes waiting to go up in flames. With the serious wildfire impacts throughout Colorado and the rest of the West, it’s a critical question. Even as I’m writing this a state of emergency has been declared in California for a wildfire in Yosemite, and others are burning in Montana. And our ability to respond to these threats is being challenged as Federal budgets are being drained empty. But the answer to where wildfire risk is highest is a bit more complicated than just locating dead trees.
Trying to make observations while driving at 65 mph or trying not to ride my brakes too much on descents was neither easy to do nor very safe. But, from what I could tell, I was looking primarily at gray-phase, dead lodgepole pines. Some comments on trees and wildfire I’ve heard are along the lines of, “Of course a dead tree is higher fire risk. You don’t burn live trees in your fireplace do you?” But research is beginning to point to wildfire risk depending on how long past mortality a tree is and what “phase” it’s in.
Research from last year attempted to sift through existing studies on tree mortality and wildfire risk with a focus on bark beetle impacts. They looked at nearly 40 studies and developed a graphical summary of how fire behavior varies with time and forest condition that includes three main phases.
The “red” phase is roughly 1-5 years after a mortality event, in this case a pine beetle outbreak. The needles are still on the tree during this period and are dry. The flammability goes up along with the crown fire potential. Crown fires are intense, difficult to manage, and are often stand-replacing in which most or all of the canopy trees are destroyed. It is thought that during this phase crown fire potential is at its highest.
The “gray” phase (which I believe I was seeing with a few red-phase trees mixed in) is the period around 5-10 years after mortality. The needles have now dropped and the crown fire threat goes down. Fuels are now building up on the ground from the dropped needles, so surface fire risk begins increasing. Also, the dead trees themselves can begin falling, thus building up surface fuel but reducing the density of standing trees and crown fire threat.
Finally, over much longer periods is the “old” phase, during which the forest begins re-growing. Surface and crown fire potential increases during this phase as ladder fuels begin building up in the understory, which can allow ground fires to move up into the canopy and potentially lead to crown fires. Also, in some cases, the regrowth may change the character of the forest.
Unfortunately, the “red” phase of peak crown fire threat is the phase we understand the least about, either due to conflicting studies or just a lack of research. As an example, one other recent study looking specifically at crown fire potential in Colorado lodgepoles found dry, gusty conditions to be a primary factor rather than the phase the trees are in.
So there’re still questions to be answered on whether all trees are created equal or not when it comes to wildfire risk (or even tree mortality itself; the subject of a follow-up post), but a basic picture is starting to emerge that may help assess high fire potential areas. This will be critical for triaging limited and dwindling resources even as demands and costs for battling damaging wildfires across the West continue to grow.
But on a larger scale, beyond this or that tree stand, a warming, drying West is providing conditions ripe for wildfire over very large areas of the region. We’ve already experienced an uptick in area burned and number of large wildfires over the past few decades. And looking into the future, some projections under continued warming from heat-trapping gas emissions show that this is a problem that will not soon go away.]]>
The asthma attack was an entirely different experience, though. What followed has gotten foggy over the years, but after some time, which must’ve seemed an eternity, the attack cleared up. I got the news that it was likely an asthma attack and given an inhaler as a constant companion. But over the years it diminished as a concern and labored breathing chalked up to being woefully out of shape.
But asthma is a serious concern. Nearly 26 million Americans suffer from asthma (which works out to about 1 in every 12 Americans). This number includes 7 million children, which is eye-opening as a parent — and brings back thoughts of how truly frightening an attack was for me, especially not knowing what was happening. (And only slightly less frightening when I did know what was going on.)
Asthma is a real drag on the economy — to the tune of $56 billion each year from hospital costs, missed school and work, and treatment. More importantly, it can be deadly. In 2009, it was estimated that asthma accounted for over 3300 deaths and that was not an extraordinary year.
So asthma deserves awareness and attention as a serious public health threat. In keeping with that, May is Asthma awareness month. Much of the activity is focused on providing information about what asthma actually is, what exacerbates asthma and can lead to attacks (including numerous triggers in your home), and outlets for information and guidance, such as Centers for Disease Control, National Institutes of Health, and American Lung Association. You can even get tips on how to tell your asthma story to the media.
Outside of the home, outdoor air pollution is a primary driver of asthma attacks and risk of experiencing one. More to the point, ozone is a leading culprit. Mention ozone and people may think of the ozone hole, which indeed would be correct. This, though, is ozone we want around as it protects people and wildlife from damaging ultraviolet radiation from the sun by blocking it very high up in the atmosphere. Ozone closer to the ground, on the other hand, is very harmful to human health and a primary component of smog.
Ozone is not emitted directly into the air. Instead, it takes a handful of ingredients to form this “bad air soup”. On the chemical pollutant side, nitrogen oxides (NOx) and volatile organic compounds (VOCs) are the main ingredients. Sources for these include activities such as driving cars, electric power generation from fossil fuels, and some industrial processes. The other two key ingredients for dangerous ozone being formed are heat and sunlight, which is why ozone alerts tend to be most common with the elevated temperatures of summer. It’s probably not surprising then that high ozone levels often occur in urban areas. It’s also these areas that are densely populated with more people at risk for exposure to ozone pollution.
We have a few control knobs with which we can dial down ozone levels and reduce asthma risk. There has been success in dealing with the chemical pollutants that form ozone. Thanks to the Clean Air Act, NOx emissions have dropped by 52 percent in the U.S. over the past three decades. Likewise, VOCs emissions fell by 63 percent over the same period. And most likely as a result, average ground-level ozone concentrations have dropped by 28 percent. This is good news and shows that those particular control knobs can work, though most states in the U.S. still have counties that violate current EPA ozone standards.
There is also a climate story here and one that threatens to offset some of the success we’ve had in cleaning up the air. I came to this connection through an EPA study that found a relationship between increased temperatures and higher ozone levels based on numerous measurements throughout the eastern half of the U.S. They termed the resulting number (i.e. the increased amount of ozone per degree of warming) the “climate penalty factor” on ozone. This relationship between temperature and ozone has also been confirmed in many other modeling studies and measurements. The risk climate change poses to harmful ozone levels has also been highlighted in the “Human Health” chapter of the recent draft National Climate Assessment report.
A colleague and I at UCS took this concept a step further and asked what this climate penalty factor means in a future, warmer U.S. Basically, we used projections of warming temperatures for the country under a couple of widely used future climate scenarios (which may be optimistic based on recent carbon emission trends) and determined how much ozone levels could increase from this warming in the years 2020 and 2050. We then ran these numbers through the EPA’s BenMAP model to see what the health and economic impacts are from these ozone increases.
The full report is of course worth reading (author bias, perhaps), but the top-line finding is that climate change’s potential impact on ozone may indeed be costly (economic and otherwise). Health impacts could total an additional $5.4 billion in 2020 alone. It’s projected that there could be 2.8 million more occurrences of acute respiratory symptoms, such as asthma attacks. And most importantly between 260 and 510 additional premature deaths are projected in that single year. All of these numbers go up in 2050 with further warming in the U.S. Not surprisingly the states projected to be hardest hit are those that are most populated, with California, Texas, and New York leading the way.
It’s fitting that this month of asthma awareness has seen a couple of important steps in dealing with the problem. First, Representative Lois Capps of California introduced the Climate Change Health Protection and Promotion Act last week. This bill directs the Secretary of Health and Human Services to develop a national plan to help the health community in creating plans for both responding to and preparing for public health impacts of climate change. Although, not named specifically, ozone pollution would surely fall under this effort.
It is also an acknowledgement of the growing body of evidence of adverse and costly climate impacts on public health in addition to air quality concerns. Also, it is not just a matter of responding to climate impacts here and those on the way, but there remain the critical efforts to reduce climate change itself to limit the severity of the impacts. Fortunately, there are myriad solutions for that, but much room for improvement on actually implementing them.
Activities and efforts to raise awareness around asthma is also a critically important step, but perhaps should extend beyond the month of May into the summer months when ozone levels are elevated and people are at higher risk. I’m not sure how to penetrate through to people’s lists of concerns beyond a steady drumbeat and clear explanation of risks.
Turning the lens on myself, having lived in areas prone to extreme weather of various sorts I’m very aware of and tuned into warnings around the more “acute” events (fairly infrequent, but high impact). On the other hand, even having studied the serious impacts associated with bad air, I still don’t notice air quality warnings until they become a deep shade of purple. That goes for heat advisories and warnings, as well.
The more “chronic” events that don’t appear as destructive and happen more frequently than say a hurricane or a blizzard tend to get minimized. But ask anyone who has lost someone to a heat-related death or an asthma attack and you’ll see quickly how it takes just one instance of high ozone or a day of extreme heat to change lives.
There’s undoubtedly more to be done, but there are clear solutions and fortunately people out there talking about them. Now we need to do some listening.
This week as fires were springing up and growing in size and impacts the National Interagency Fire Center released their monthly fire outlook that covers the bulk of the summer fire season. When looking at the maps of fire potential, the eye is immediately drawn to the growing field of red spreading throughout virtually all portions California and up into Oregon and Idaho. Likewise, much of New Mexico and portions of Arizona will see increasing fire risk for the next few months pulling in portions of southern Colorado.
Basically, we can look to precipitation (or lack thereof) to get a top-line idea of what’s driving the activity both current and forecasted for the rest of the summer. Over the past month, virtually all portions of the West that are experiencing fire or elevated fire risk are some shade of red, meaning below average precipitation. Areas in Southern California dealing with fire outbreak saw less than 2 percent of normal precipitation. And recently New Mexico rose to the top of the ranks of drought-stricken states with much of the West under severe, extreme, or exceptional drought conditions. Sadly, there is no relief in sight as we get into the depths of the summer fire season as drought conditions are expected to persist through July for most of the West, in part driving the forecasted heightened fire risk.
Many factors play a role in fire risk and outbreak. How much fuel is available which can touch upon past land management practices and perhaps disturbances such as insect outbreaks and tree mortality. There is always an ignition risk from either lightning strikes or a campfire that was not fully put out. But dry fuels (trees, brush, and duff) represent a major risk factor. And the continuing widespread drought has both been priming current conditions and will likely continue to do so throughout not only this season, but further down the road as well.
Fire has always been a part of the West. For those of us who live or have lived there it is part of the trade-off for endless big sky vistas and majestic mountain landscapes. But it appears that it is an impact that is growing as the number of fires and area burned have increased over the past few decades and the fire season has lengthened. At the same time spring and summer temperatures have increased along with earlier spring snowpack melt overall and are likely driving increasing fire risk. Naturally, questions arise as to whether response plans are and will continue to be sufficient, how will sequestration and shrinking budgets affect things, what actions are local cities and towns taking to help reduce risk, and what does the future hold for wildfire in a warming climate. We’ll have to leave the answers for another post.]]>
Although many rivers remain above flood stage, hopeful stories are beginning to emerge that relief may have arrived as the record rains have departed the region. However, as the Midwest is out of the extreme rain woods for now, it remains in the thick of potential health impacts that linger well after rivers have crested and waters have retreated. The huge sigh of relief that the flooding is over is more than welcome, but the region needs to remain vigilant as the impacts story continues to unfold in sometimes unrecognized ways.
Loss of life rightfully captures the headlines on flood impacts. So far four deaths have been attributed to this flooding. Floods have historically been one of the most deadly types of disasters in the U.S. Over the 30-year period from 1982 to 2011, an average of 93 live were lost due to flooding each year, which makes it deadlier than lightning, tornadoes, and hurricanes over that same period. Much of this loss of life is due to drowning.
But beyond the immediate dangers to human life during the flood, more hidden and less obvious threats are present both during the flood itself and well after the waters have begun to recede. UCS colleagues and I looked into more detail at some of these that aren’t always on peoples’ radars or may be wholly unaware of — as I was prior to this work. It’s these hidden impacts that people in the Midwest will likely be confronted with over the coming days and weeks.
Drowning while driving was probably the risk that caught me most by surprise. Of the flooding deaths in 2010, almost half of them were a result of attempting to drive through flooded areas. In the current Midwest flood, two men separately drowned while attempting to drive through the same swollen creek in Indiana. The risk is such that the National Oceanic and Atmospheric Administration actually has a dedicated campaign, “Turn Around, Don’t Drown”, for this issue.
Water is particularly at risk during flooding due to contamination, with serious health implications. Drinking water and recreational waterways can be contaminated with sewage, agricultural waste, chemical pollutants, and animal waste. A vivid picture of these risks is hog farm waste spilling over its storage lagoon and into the surrounding areas after Hurricane Floyd in North Carolina — one of the more unpleasant of numerous unpleasant images we came across for our report. In another well documented case, after a very heavy rainfall event in Milwaukee in 1993, an outbreak of the parasite cryptosporidium occurred and affected more than 400,000 people.
The risk of outbreaks and contamination may be heightened for areas in the Midwest now dealing with flooding as there is a high concentration of combined sewer overflow systems there that are more prone to backup and contamination during heavy rain. As I’ve found by encountering empty shelves when a tropical storm or hurricane is on the way, stocking up on water is the first line of defense. But beyond that the Centers for Disease Control (CDC) have useful information for dealing with flooding and its aftermath.
Signing up for local boiled water alerts is probably also a good idea even for those not directly impacted by flooding as drinking water may be coming from distant sources that have been affected. This raises the more general question of “do you know where your drinking water comes from?” I don’t think I do.
And saving perhaps the most hidden risk of all for last, mold can pose serious health threats and linger well beyond the actual flood. Water anywhere in the home can lead to a mold outbreak and this risk is obviously going be heightened during flooding.
Mold can lurk behind drywall, under carpeting, in furniture, or in insulation, making it hard to detect. It can trigger allergic reactions and respiratory symptoms, including asthma attacks. This leads to a real drag on the health care system and the economy; some estimate annual expenses of between $2.1 and $4.8 billion. Some studies have shown that infants and children exposed to mold are more likely to develop asthma than those who haven’t. Unfortunately, not only can mold be difficult to detect, but it is also costly to remove once widespread. Drying out affected areas immediately, if possible, reduces risk of outbreaks and is the first step. Again the CDC provides very helpful information in dealing with this threat.
Managing risk going forward
Right now the conversation needs be focused on helping those in the Midwest deal with flooding impacts already being felt and those that could still be lurking. But asking questions about the next flood, and if cities and the region are going to be prepared, is critical as there will surely be more. There is ultimately an entire chain of risk factors that influence flooding and impacts that can be addressed at the national level all the way down to individuals.
Climate change in the region represents a growing risk factor for flooding. The Midwest has seen a 45 percent increase in the heaviest precipitation events between 1958 and 2011, increasing the risk of dangerous floods. Over roughly the same period temperatures in the Midwest increased twice as fast as the entire period since 1900. If you look at the period since 1980, temperatures increased three times as fast. Correlation doesn’t always imply causation, but these trends fit with our picture of how heavy precipitation tracks with temperature. The basic physics behind this is that warmer air can hold more water vapor before it rains out, so the old adage “when it rains it pours” is unfortunately becoming more apt. Future projections show the same trend continuing as these heavy events become more likely under continued warming in the region. So limiting warming is one control knob to reduce flooding risk by dealing with the problem before it hits the ground.
Other possibilities open up once the water does hit the ground. Cities can play a role in how storm water is managed. There seems to be a great deal of opportunity in improving sewers, especially in the Midwest and Northeast. Chicago, which was in the thick of the deluge, has taken action by installing rain blockers, investing in rooftop and rain gardens, and increasing permeable surfaces to help manage runoff and flooding. Cities can determine if development should take place in areas prone to flooding as way to address risk. City and state health departments can also ensure that their response plans and resources to be mobilized are in place.
But there’s also a strong role for the individual in protecting themselves and their families from flooding impacts and reducing risk. Maybe the most critical step is being aware of the myriad health impacts beyond the obvious and developing effective responses to those.
I’ll interject my own flooding story here, which while paling in comparison to what others are currently facing, illustrates the point about what individuals can do. My house was partially flooded during a tropical storm prior to working on our flooding report. I was completely unaware of all of the potential impacts involved and how to address those, beginning with not buying any potable water beforehand, to being told by my landlord that I should probably put fans on the flooded areas, to not turning off the power before going into my basement, to not checking to see if my faucet water was safe to drink.
Luckily, we came out okay, but looking back the biggest risk factor for me was not being aware of what exactly I was facing. So while the work at UCS started with how a warming world increases the risk of flooding, it ended up being about the actual, household-level impacts and especially those that are hidden. That’s what Midwesterners are going to be facing in the coming days and weeks. Sadly, they’re not in the clear yet.]]>
Looking further back, the past 35 years have all exceeded the 20th century average global temperature. That’s a generational shift. Half the U.S. population is 35 or younger, so half of all Americans have never lived through an “average” year.
Some scientists call this a “new normal,” but there’s nothing “normal” about it compared to the climate many of us grew up with. As heat-trapping emissions from burning coal and gas and destroying tropical forests build up in the atmosphere, the climate is changing faster than anything nature would produce on its own. Given how quickly climate change is unfolding, today’s “new normal” will quickly become the “old normal” and old records will keep being broken.
One of the most immediate ways we experience a changing climate is through shifts in weather extremes. And the weather we experienced this year gives us a strong taste of what future climate change could deliver.
This year’s summer heat waves were some of the hottest in our history. Longer, more intense heat waves are one of the clearest links scientists see between global warming and changes in weather.
If there were no climate change, we’d be just as likely to break record low temperatures as we are to break record highs. But the United States broke about 300,000 record highs but less than 150,000 record lows over a recent ten year time period. Over time, new heat records are further outpacing new cold records.
We also saw drought cover more than half the country, withering crops and decimating cattle herds. Scientists also see a clear link between climate change and increased drought in some regions. Consequently, farmers, ranchers and water managers can no longer count on “normal” precipitation patterns.
Finally, we saw Sandy, a storm with a price tag in the tens of billions of dollars. As our planet warms, ice on glaciers melts and the ocean heats and expands, making sea levels rise. In New York City, water levels are 11 to 16 inches higher than they were a century ago, allowing Sandy to ride in on a super-high tide. Now every coastal storm has the potential to punch further inland and inundate more homes and businesses.
Future climate change will depend on the energy choices we make today and how the climate system responds to our emissions. The United States and other countries have pledged to limit warming to no more than 3.6 degrees Fahrenheit above pre-industrial levels. But policies currently in place won’t meet that goal. Instead, we’re on track to experience more than 7 degrees of warming by the end of the century.
That wouldn’t be a “new normal.” That would be a different planet.
Our own National Academy of Sciences, founded by Abraham Lincoln to inform policymakers about science, concluded that climate change is occurring, is caused largely by human activities, and poses significant risks for human and natural systems. Nearly every national academy of science the world over and scores of scientific societies affirm these basic findings.
But misinformation from special interests has sown doubt and confusion about climate science among the public and policymakers.
That has to change. There’s nothing ideological or partisan about first responders planning for the toll increased summer heat can take on seniors. Or farmers taking a hard look at the future for their crops. Or coastal planners anticipating how fast sea levels are rising near valuable beaches.
Post-Sandy, conversations about climate change have a new urgency.
We can be more creative in planning and building resilient communities. There are win-win solutions to address the underlying causes of climate change. For instance, energy efficiency reduces heat-trapping emissions and also helps power companies manage demand during heat waves. Reducing emissions that cause climate change can also help improve air quality and health.
Policymakers shouldn’t put climate change — and the best available, most accurate science, that informs our responses to it — on the back burner.
As our climate changes, it will almost certainly keep delivering more wake up calls like this year’s extreme weather. It’s time for us to get to work finding solutions and making sure we’re prepared for the impacts that are still to come.
**This post originally appeared as an op-ed carried by the McClatchy-Tribune Information Services, which provides content to dozens of newspapers across the country.
Not only can such natural defense systems reduce vulnerability to and impacts from events like Sandy, but they can often be done less expensively than built solutions while providing other important benefits at the same time.
Adaptation to climate change and associated impacts has previously been grouped into so-called “soft” and “hard” approaches. The “soft” approaches include generating and spreading relevant information, raising public awareness, and ensuring functioning institutions, such as public health departments. The “hard” approaches focus more on the built environment, such as seawalls and levees. It has been suggested that ecosystem-based adaption can provide a third way towards building resilience against climate impacts.
The beauty of relying on natural, healthy ecosystems is that they provide a wide array of services and valuable potential co-benefits, including air quality regulation, water purification, genetic resources, food, livelihoods and jobs, tourism and recreation, and even spiritual and aesthetic values. With coastal storms like Sandy, however, the important benefits are in coastal protection.
Healthy coastal ecosystems can provide defenses against dangerous storm surges that can inundate coastlines. Mangrove forests include various types of trees that all grow in coastal, saltwater environments, including areas in the Caribbean and along the Gulf Coast. Mangroves essentially provide a break against damaging waves by reducing their height before reaching further inland and causing damage. In fact, one study found that areas with mangroves experienced significantly less deaths than those without when a cyclone struck India in 1999.
Coral reef systems function in much the same way as mangroves. They provide surfaces that can break up waves before pounding the coastline. Up to 90 percent of the energy from waves can be absorbed by reef structures and this can have substantial value in avoided coastal impacts. Reefs also provide services beyond protection from storm surge. They serve as critical habitat for numerous marine species and have been called the “rainforests of the ocean.” This can lead to economic benefits through local fishing industries (in part by providing productive spawning grounds for fish), recreational tourism, and the many under-appreciated benefits of biodiversity.
For areas that don’t have mangroves and reefs (e.g. much of the U.S. East Coast), other natural defenses can reduce storm impacts. Barrier islands like those along North Carolina and New Jersey can shield the coastline behind them. Likewise, properly functioning river deltas and wetlands can reduce storm surge and flooding vulnerability. A degraded Mississippi River delta has been implicated in increasing the vulnerability of New Orleans and surrounding areas to storms like Katrina and Rita.
Natural approaches can be cost-effective
A recent review study took some case studies and put dollar figures on ecosystem-based adaptation versus hard infrastructure. For instance, in the Maldives, an island nation threatened by sea level rise, it is estimated to cost $1.6-2.7 billion to replace natural reefs with built protection like seawalls. In contrast, the cost of preserving existing reefs may be only in the tens of millions of dollars per year, with potential co-benefits of around $10 billion annually in tourism and fisheries.
Likewise, restoration of wetlands around New Orleans is estimated to a few dollars per square meter. The return on wetlands in the Mississippi delta is estimated at $12-47 billion per year in total ecosystem services. A flood wall can be heightened by one meter for $7-8 million per kilometer. This can reduce flood risk, but does not provided the additional value through the many ecosystem services of natural defenses.
Global change has not been kind to these natural defenses and is putting their continued services at risk. Coral reef systems face numerous threats from many different directions. Overfishing, development, and agricultural pollution run-off have been culprits historically. Now ocean acidification and rising water temperatures have emerged as serious threats and both stem from carbon emissions. These trends are projected to continue, increasing the impacts to reefs.
Mangroves also are being lost with some estimates at 30-50 percent globally since the 1940s. These losses are due, in part, to development, sea level rise, and pollution drainage. This is especially troubling as mangroves, along with sea grasses and salt marshes, have been termed “blue carbon” and are significant carbon sinks. Not only are we losing them as a player in climate adaptation, but we are also losing them in climate mitigation. However, recent work has shown that if carbon emissions were to be priced at a modest $10 per ton then mangrove habitat destruction could be greatly reduced. It would become more valuable from a dollars and cents perspective to leave mangroves intact.
Ecosystem-based adaptation may not be appropriate or applicable in every case. However, it should definitely be explored as an option when possible. Not only do we get resilience and protection from damaging coastal storms, but it often comes with lower net costs and myriad other ecosystem benefits for free. That cannot be said about simply building a higher levee.]]>
As of last weekend, the death toll from Sandy stood at more than 180 people from the Caribbean to Canada, with more than 110 deaths in the U.S. alone. Many people were killed by falling trees. Drowning, touching live electric wires, and carbon monoxide poisoning from generators run in enclosed spaces were other frequent causes in this sad litany.
The hidden health risks associated with flooding from events such as Sandy include waterborne diseases contaminating drinking water and bacteria and sewage in local waterways. The latter was evident in Hoboken, New Jersey, one of the worst hit areas on the East Coast, where thousands of people were stranded in their homes while the streets filled with sewage-contaminated floodwaters. National Guard troops were forced to go in and stage a massive rescue effort.
Research has shown that over half the outbreaks of waterborne diseases in the U.S. occur in the wake of heavy rains and flooding such as we saw with Sandy, and that floodwaters may contain more than a hundred types of disease-causing bacteria, viruses, and parasites.
Long before Sandy became an unprecedented meteorological phenomenon and threatened havoc on the heavily populated and developed East coast, it was taking a significant human toll in the Caribbean.
Most recent estimates of lives lost in this region are around 69. However, this number may be off quite a bit as making mortality estimates can be quite challenging in a developing country such as Haiti, especially in the weeks to months right after the disaster. Also, these numbers likely represent fatalities associated with direct physical trauma or drowning. The health impacts can continue long after the waters have receded.
In less developed countries, access to clean drinking water is already a constant struggle for many. A flooding event, such as that from Sandy, only compounds this problem. The more hidden health impacts of a major disaster may take time to emerge—as demonstrated by a major outbreak of the water-borne disease Cholera in Haiti a year after the earthquake. Many people rely on public waterways in these regions, due to lack of water supply infrastructure. These can be at high risk of sewage contamination during floods and pose a serious public health threat.
Though the storm has passed, the hidden health risks from flooding will likely continue for some time. As we rebuild our homes and infrastructure, we can’t take our eyes off of our health.
Flooded homes and buildings create a breeding ground for mold, which can cause debilitating respiratory and neurological problems. Exposure to mold in inundated structures can, among other things, increase the risk of asthma in children and pose a lingering health threat well after the flood. But in resource-strapped areas funds for mold removal and cleaning up waterways may be non-existent. Mental health problems, such as stress and depression, also tend to increase in the wake of extreme weather disasters.
Losses from extreme events often have dollar figures attached to them as a measure of their destructiveness. But how does one put a dollar figure on a human life? How does one account for the debilitating toll from all the injuries and sicknesses caused by Sandy?
Public health impacts from extreme events are real and no less of the story than losing buildings, homes, or transit systems. But putting a true cost on them is challenging.
As we move forward and prepare for the next one it will be critical to have protection and response measures in place to reduce fatalities from drowning, electrocution, and physical trauma. But no less important is knowing what other lingering health risks we face from these events and what we can do to prepare for those.
We have to search for ways to build communities that are more resilient to the ravages of extreme weather events in a warming world.
This post was co-authored with Rachel Cleetus, UCS Senior Climate Economist.]]>
A group of prominent scientists in this field recently described their concerns and scientific impacts in a letter to Science. So why is understanding the carbon cycle actually important for us?
Over the past 150 years or so a lot of carbon dioxide has been dumped into the atmosphere through human activities, such as burning fossil fuels and deforestation. This carbon dioxide is very effective at trapping heat and changing our climate.
The carbon cycle reduces the impact of these emissions; natural sinks for carbon dioxide remove over half of what we put into the air. Roughly half of this service is provided by land vegetation (plants take up carbon dioxide during photosynthesis to produce stems, foliage, and roots) and the other half by ocean uptake. So, for every billion tons of carbon emitted to the atmosphere, where it is a potent heat-trapping gas, less than half remains there. Land and oceans take away the rest.
This climate service does not come without a cost, though, as the oceans are increasingly becoming more acidic as they remove some of our carbon emissions. The carbon cycle is also very complex. Some of the carbon emitted into the atmosphere remains for hundreds to hundreds of thousands of years until it is finally removed by very slow processes such as deep ocean mixing and rock weathering. This gives rise to the concept of “irreversible” climate change. So the carbon cycle helps us in some ways, but is very nasty in others.
Putting aside the discussion of whether climate targets (i.e. how much warming we think we can live with) are a good idea and at what level they should be, let’s assume there is some level of warming we don’t want to exceed. In international climate negotiations this has been a global increase of 2°C (3.8°F).
It has been shown that there’s a “simple” relationship between total (or cumulative) carbon emissions and long-term temperature increase. A portion of what we emitted a hundred years ago is still having an effect, so we have to look at emissions since the Industrial Period began. So essentially we have a bank account of carbon we can spend (or emit) if we were to stay below the internationally proposed temperature goal. The “simple” is in quotes, because there are uncertainties about how much we have in our account.
To hit a target we might have more in our account than we thought or maybe we have less. Part of this uncertainty in how much we have to spend is due to not knowing exactly to what degree the carbon cycle will continue to bail us out. If needing to know exactly how much carbon we can emit is important then we need to know as much about the carbon cycle as we can. Otherwise, we may be well off the mark.
Some readers are likely familiar with what may be the iconic picture of the carbon cycle: the Keeling curve. This curve (pictured below) shows a steady upward march of carbon dioxide in the atmosphere. The sawtooth pattern captures the “breathing” of the Northern Hemisphere with spring pulling down CO2 from the atmosphere as plants regrow after winter and release it back to the atmosphere as they die or lose leaves in the fall.
As far as climate is concerned this is the important measurement as climate is forced to change in one direction or another in large part due to the concentration of excess carbon dioxide in the atmosphere. But this one curve misses many of the other important questions such as: Where is the other half (or so) of our emissions going if not into the atmosphere? Is the land uniformly taking up carbon or are there strong sinks in areas such as the northern mid-latitudes or the tropics? And how are these changing over time? This is just to name a few questions among the many.
Much of the information needed to answer these questions comes from the worldwide network overseen by NOAA, which includes flask air sample sites, tall towers, and aircraft. This network provides critical carbon cycle information at local and regional scales. Knowing which ecosystems and landscape types are sinks or sources for carbon and to what degree; and how these sources and sinks respond to disturbances, such as drought and wildfire, are questions that will help determine how the carbon cycle will evolve under continued carbon emissions and warming.
As of the last IPCC report, models generally show that the land and ocean will continue to take up emitted carbon, but climate change will likely reduce this service. There is uncertainty about how much this will decrease over the 21st century, which obscures how much we actually have in our “emissions” bank account. Reducing this uncertainty makes on-the-ground and in-the-air measurements that much more important.
Satellites, such as the Japanese GOSAT and NASA’s eventual OCO-2 provide carbon cycle measurements covering very large areas of the planet and are an important component to our understanding, but they still need to be validated with “in-situ” measurements, such as those currently under threat.
Many important programs are on the chopping block across the sciences and, more broadly, in sectors across the country in these times of tight budgetary constraints. It would not be fair to comment on which should stay and which should go. That is Congress’ job.
I will say, though, that the NOAA greenhouse gas monitoring program’s budget is currently $6 million in a total federal budget that is in the trillions of dollars. This seems, relatively speaking, like a very small price to pay for information that is so central to our understanding of how the planet works and carries such large implications for society.
PS: For those wanting to learn more about the carbon cycle I highly recommend the general-audience accessible and informative book by David Archer, The Long Thaw.]]>
The simplest climate model is only one equation and gives the temperature a body (like Earth) must be at to give off as much energy as it’s receiving from a source (like the sun). It is a simple balancing of energy flow in and energy flow out. Things get complicated in a hurry when you add greenhouse gases, ice sheets, and oceans, but the story never stops being one of balancing energy flows. Indeed, climate change arises when this balance of energy flow is disrupted and much work goes into trying to measure these flows from the deep seas all the way up to low-Earth orbit.
The energy flows of an entire planet are important to know, but it’s also just as important for on-the-ground conditions to know how incoming energy is divvied up. One only has to step outside on a hot summer day after a rain shower to see or feel this. The energy in would be from the sun. When it’s dry out that energy is primarily absorbed by the ground and heats up — sensible heat is the technical word. In this case the sun’s energy ends up heating the air just above the surface making it feel hot for us. Once the ground heats up it also can dissipate that heat by re-emitting it back to the air as infrared heat. This heat can be absorbed by heat-trapping gases in the air, which in turn re-radiates that energy in all directions. Infrared energy is a longer wavelength than sunlight and may be more familiar as those “night goggle” images of people and pets outside in the dark.
Now comes a nice rainstorm that soaks the ground and puddles abound. You’ll now notice that even after the clouds have parted and the sun is back out it stays cool for a while. That’s because now the sun’s energy can take a path that doesn’t involve heating the air just above the ground. That’s through latent heat.
Basically, the sun’s energy is going into heating and evaporating the various puddles and soggy surfaces. Energy is being carried away by this evaporation that may have otherwise gone into heating the ground and air near the surface. This energy is released somewhere else as the moisture eventually condenses out as clouds up in the atmosphere. It’s only after the surface moisture has evaporated (e.g. no more puddles and dry parched soil) that the temperatures begin to climb again.
This energy partitioning has important implications for drought exacerbating heat. It’s also important in, for instance, ecosystems in determining how they can affect their surrounding climate.
There is a growing body of scientific literature looking at the connections between drought and high temperatures. The latest IPCC Assessment report included a section looking at these relationships and reported that often higher temperatures occur with lower precipitation and vice versa. There has been other work that discusses how low soil moisture (dry conditions) “primes the pump” for subsequent heat.
One study found that the distribution of daily maximum temperatures shifts with soil moisture content and that the hotter end of the distribution feels greater effects than the cooler end. They also found that in some regions elevated temperatures can hang around for weeks after the low soil moisture conditions. Also, reduced soil moisture was found to have played a role in elevating temperatures during the killer European heat wave of 2003.
Finally there was a recent study that found for many parts of the world, including North America, that the occurrence or risk of experiencing above average numbers of hot days increases 60-70 percent after periods of reduced precipitation. This study even zoomed in on Texas, which has been faced with a crippling drought over the past year. Dry years for Texas led to increases in the number of hot days experienced during those years. This probably won’t come as a surprise for people living there.
So, there are some pretty simple explanations linking precipitation (or lack of), surface moisture, evaporation, and temperature. It is a more detailed and intricate dance than presented here, but the short message is if there’s a drought there’s likely a heat wave lurking around the corner. And as we’ve seen in this series, so far, the impacts can be massive.]]>
There are many ways to measure heat, including maximum temperature and heat index. We chose to look at what are called air masses. Think of the large umbrella of air over a city that is described by its temperature, dew point (a measure of humidity), wind, and cloudiness. We were ultimately concerned with how changing summer weather impacts human health. Air masses do this nicely as they capture multiple weather variables that the body responds to in one fell swoop.
We focused on two types of air masses that have historically been associated with negative impacts to human health. The first is the very dry and hot air mass. The other is hot and humid.
We looked at the most extreme subset of the hot and humid air masses. We also took a look at a class of air masses that are dry and cool. These are the nice, summer days that provide relief from the heat. It would stand to reason that if more summer days are coming in the form of stifling heat then there would be less cool days.
The short version of the story is that most of the cities we looked at are now, on average, seeing more hot and humid and hot and dry days per summer than they did five or six decades ago. And to no real surprise these trends are accompanied by an overall decrease in cool and dry summer days.
We also found rather strong trends in increasing overnight temperatures in the dangerous air masses. This has health implications since people often rely on cooler nighttime temperatures to provide relief from oppressive daytime heat. It appears that for the dangerous air masses this relief may be decreasing as time goes on.
Finally, the number of three or more consecutive day events of these hot air masses occurring each summer has also increased. The number of these “heat waves” may at first seem modest as we’re seeing increases of up to four per summer over the record. However, the impacts of any one event can be substantial. A one-off day of hot weather can be manageable, but string together many days in a row and the situation can become dangerous.
One thing our study did not do is to directly determine if the trends we are seeing in the Midwest are due to human activities. However, we looked at smaller, partner cities and found similar trends to the larger cities. This implies that the heat trends in the larger cities are not being driven by urban heat island effects alone. The picture that emerged is consistent with a general climate trend. Looking at 60 years of data also rules out the case of trends arising from short-term events, such as a strong La Nina.
Heat presents a real threat to human health. It has been responsible for more deaths than all other natural disasters combined over the period 1979-2003. The trends we found aren’t based on models, but on real weather data over the past six decades. This is what folks in the Midwest have actually experienced. This also appears to be a risk that is not going away. Many studies have projected increases in future heat waves and temperatures in general, including for the Midwest. All of our study cities are currently engaged, at some level, with adaptation planning as we discuss in the report, but will it be enough for a hotter future?]]>