Environmental degradation is widely recognized to contribute to human illness. However, little research has been done to investigate the impact of human illness on the environment. This is a critical question particularly for the millions of people around the world who depend on natural resources for food and income while coping with high burdens of infectious diseases.
When people are sick, they often alter their use of natural resources in ways that harm the environment, according to a new study reported in the Proceedings of the National Academy of Sciences.
Specifically, the researchers examined how illness influenced fishing practices in the community around Lake Victoria, Kenya, which has high rates of HIV and other illnesses. They interviewed about 300 households several times over 16 months, collecting and analyzing data about household fishing habits and mental and physical health. They found that healthy people are better for the environment.
“Studies suggest that people will spend less time on their livelihoods when they are sick, but we didn’t see that trend in our study. Instead, we saw a shift toward more destructive fishing methods when people were ill,” said lead author Kathryn Fiorella, PhD, a postdoctoral scholar at Cornell University, in a recent news release.
The study found that sick fishermen were less likely to legally fish in deep waters or overnight to target the more sustainable mature fish. Instead, they used destructive fishing methods that were concentrated along the shoreline — such as using a beach dragnet that captures a high proportion of juvenile fish and disturbs shallow fish breeding habits.
Basically, sick fishermen just wanted to get their catch quickly with less energy. They were focused on their short-term goal and not worried about depleting the fish stock.
In light of this study, the authors suggest that institutions and organizations focused on protecting the environment may need to more deeply consider the health of communities. The paper concludes, “Our study emphasizes the importance of considering health, governance, and ecosystems through an integrative lens.”
This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.
Vaccines are arguably one of the most important inventions of mankind. Unfortunately, vaccines must be produced and stored in an environment with very tight temperature regulation – between 36 °F and 46 °F – to keep the vaccine bugs alive. So vaccine delivery is a major problem due to the absence of reliable refrigeration in many remote countries.
Approximately 30 million children worldwide – roughly one in five – do not receive immunizations, leaving them at significant risk of disease. As a result, 1.5 million children under the age of five die annually from vaccine-preventable diseases, such as pneumonia and diarrhea. Perhaps more surprising, almost half of the vaccines in developing countries are thrown away because they get too warm during delivery so they are no longer viable. Some administered vaccines are also ineffective because they froze during transport, but there is no easy way to test this.
Scientists at Lawrence Berkeley National Laboratory (LBNL) are trying to solve this vaccine delivery problem by developing a portable solar-powered fridge. Fabricated entirely at LBNL, their portable solar-powered vaccine fridge will be transported by bicycle or motorcycle in remote areas of the developing world. Zach Friedman and Reshma Singh are leading the project as part of the LBNL Institute for Globally Transformative Technologies, which seeks to bring scientific and technological breakthroughs to address global poverty and related social ills.
The team’s first prototype portable fridge uses a thermoelectric heat pump, rather than a traditional vapor compression heat pump that relies on a circulating liquid refrigerant to absorb and remove heat. The thermoelectric chips were initially developed to keep laptops cool, so laptops could be made thinner without fans. The technology was adapted for this global application to reduce the size and weight of the fridge.
Their portable units have a one to three-liter capacity, much smaller than standard solar fridges that are typically 50 liters or more. Once the fridge cools down to the right temperature (36 °F – 46 °F), it is designed to run within that temperature range for at least five days without any power, at an ambient outside temperature as hot as 110 °F.
Before the researchers can field test their first prototype fridge in Africa, they need to pass the World Health Organization’s Performance, Quality and Safety testing protocol for products used in immunization programs. They are currently busy performing in-house testing at LBNL to ensure that they pass the formal tests, which will be conducted by an independent laboratory in the UK.
“We aren’t in the process of field testing yet, but we have established field testing agreements in both Kenya and Nigeria and have locations identified,” said Friedman. “We expect to start testing this coming year.”
Meanwhile, they are continuing their portable fridge development. “Currently, we are pursuing both thermoelectric and vapor compression heat pumps, even for these smaller devices,” explained Jonathan Slack, lead engineer. “It is not clear which will win out in terms of manufacturability and affordability.”
They are also developing a backpack version of the vaccine fridge. However, human-carried devices have to meet stricter World Health Organization standards, so they are focusing at this stage on the small portable fridge instead.
Ultimately their goal is to make it easy for health care workers to deliver viable vaccines to children in remote areas, solving the “last miles” of vaccine delivery.
Two hundred years ago most of the Sacramento-San Joaquin Delta (Delta) was a vast wetland. Early settlers built an intricate levee system to create dry “islands” suitable for farming.
Today, these levees help protect people, property, natural resources, and infrastructure of statewide importance. The Delta is home to more than 515,000 people and 750 animal and plant species; supplies drinking water to 25 million Californians and irrigation water for the majority of California’s agricultural industry; and attracts 12 million recreational visits annually.
Unfortunately the Delta levees are vulnerable to damage caused by floods, wave action, seepage, subsidence, earthquakes, and sea-level rise. While the occasional levee break is a fact of Delta life, a catastrophic levee failure could cause injury to people or loss of life. It could also damage property, highways, energy utilities, water supply systems, and the environment —all with regional and statewide consequences.
A variety of actions can be used to reduce flood risk in the Delta. The Delta Levees Council is developing a strategy to evaluate and guide future California investments to reduce the likelihood and consequences of levee failures. Interested? Learn more about this project and get involved by attending public meetings.
Do you have expired or unused prescription drugs stacked up in your medicine cabinet? It’s not safe to flush them down the toilet or throw them out with the trash. But you can get rid of them safely, easily and for free at sites across the US tomorrow. Yep, it is National Prescription Drug Take-Back Day on Saturday October 26 from 10 am – 2 pm. Drop them off at a local collection site.
In the northernmost city of the United States – Barrow, Alaska – the treeless flat tundra looks stark and forbidding to many people. The permanently frozen soil (permafrost) is only capable of supporting plants like moss, heather and lichen and the temperatures can drop as low as -60 °F.
However, this tundra is a mecca for climate scientists like Dr. Margaret Torn, co-lead of the Climate and Carbon Sciences Program at Lawrence Berkeley National Laboratory (Berkeley Lab). Torn just returned from performing field experiments near Barrow. She is part of the 10-year Next-Generation Ecosystem Experiment, a large collaboration of scientists and engineers who are trying to better understand the Arctic terrestrial ecosystem so they can improve vital climate predictions. These scientists are finding new ways to study the complex ecosystem of the Arctic landscape, including looking deep into the soil.
“Soil is a big mystery,” explained Torn. “We don’t understand why soil holds so much carbon. And we don’t understand how a warming climate will affect soils. The question being whether a warming climate will result in carbon transferring from soils to the atmosphere as greenhouse gases, creating additional global warming.”
Soils are an important part of the carbon cycle. In the natural carbon cycle, carbon dioxide is taken up by plants and photosynthesized. If the plants aren’t harvested for food or fuel, they decay and their organic matter makes its way to the soil where it is processed by tiny microbes – bacteria and fungi – that release the carbon dioxide back into the atmosphere.
Soils are critical because they store about 2.3 trillion tons of carbon – more than twice as much as the atmosphere or vegetation. In comparison, burning fossil fuels releases about 9 billion tons of carbon dioxide per year.
Soils are also a long-term reservoir of carbon. Carbon cycles very slowly deep in the soil, where it can remain for 50,000 years. So a critical question is how long will soils contain these rich deposits of carbon? Will the carbon stay put? Or will it enter the atmosphere in the near future, greatly amplifying climate change?
The Arctic tundra is an area that is particularly worrisome. Cold temperatures suppress microbial growth, which helps trap the vast stores of carbon in the soil. But global warming is causing the Arctic permafrost to thaw, triggering the microbes to become active and respire carbon dioxide into the atmosphere.
Torn’s group drills wells in the Alaskan ground to directly measure the flow of carbon dioxide and methane from the land to the atmosphere. They measure these gas flows in areas where the permafrost is intact and where it is thawing, trying to understand the environmental variables that are controlling the release of greenhouse gases.
They see very high methane concentrations in areas where the permafrost is thawing. However, this summer they found that in some areas specialized microbes consume this methane before it is released, so carbon dioxide is released into the atmosphere instead. This is good news for the environment, because carbon dioxide is a less potent greenhouse gas than methane.
They also take soil core samples from different regions in Barrow, and then incubate them at different temperatures back home at Berkeley Lab. They find that one handful of soil has thousands of different kinds of microbes and billions of cells, which respond to the environment differently. They also determine how old the carbon is in the samples using carbon-14 dating.
“One thing we’ve seen this summer is that the carbon that is being decomposed just above the permafrost is more than 2500 years old,” described Torn. “So this place that we’re studying has been storing carbon for a long, long time. But that carbon can be decomposed and released as carbon dioxide very quickly when the conditions are right.”
These results have been validated by other recent experiments, but they contradict the old belief that carbon hidden deep in soil will remain there forever due to the soil’s material properties. “The field is evolving rapidly. We’re trying to unravel the mystery of why we see older carbon in the soil, trying to create a more realistic view,” explained Torn. “It is more complex. It’s the interaction between the entire ecosystem and the material properties that’s important.”
Of course the more complicated, realistic view makes climate modeling more challenging. Climate models are computer programs that simulate how the climate has changed in the past and how it will change in the future. They are critical to understanding our planet and how to limit the impact of human activity upon it. But scientists know that their climate models are wrong when it comes to soil carbon. This is why scientists need new data, like they are acquiring in Alaska, to test and improve their models.
“We can do so much better than we’re doing,” exclaimed Torn. “So we feel pretty confident that we can make improvements. It may not be perfect, but our work is going to make predictions more robust and believable.”
This is a repost of my KQED QUEST blog titled, “The Great Escape: How Soil Protects Us from Carbon Emissions.”
Scientists will talk about their latest research findings on how the earth’s climate is changing, from the arctic to the rainforest. Participating speakers will address critical questions: What happens when the permafrost thaws? What do computer models predict about our future climate – floods, droughts, hurricanes and heat waves? What role do our forests play in carbon absorption? What kind of carbon tax might actually work?
Come find out what to expect and if there is anything you can do about it!
Everyone loves the idea of solar power — heating and cooling your home using the sun as a clean, free source of power. It sounds like the ultimate way to lower your carbon foot print! However, solar cells are expensive and typically only about 15% efficient, as I discussed in an earlier blog.
In order to make solar power more practical on a wide scale, a lot of research is underway to increase solar power efficiency. Stanford researchers have just reported a significant breakthrough in such solar power research, as described in their new paper in Nature Materials. They have developed a novel solar technology that uses both the light and heat of the sun to generate electricity. This new technology could double solar power efficiency and make it more affordable.
When most people think of solar power, they think of rooftop solar panels. These sort of solar panels (or arrays of photovoltaic solar cells) use expensive semiconductor materials to convert photons of light into electricity. The photons from sunlight are absorbed by the semiconductor material, so the energy from the photons is given to the electrons in the semiconductor. The energy given to an electron can “excite” it from the valence band to the conduction band, where it is free to move around within the semiconductor to produce electricity. Solar panels basically convert solar energy into direct current electricity. However, these types of solar panels aren’t very efficient. If an excited photon doesn’t absorb enough energy, then it can’t make it to the conduction band to produce electricity. On the other hand, if an excited photon absorbs more energy than needed (to make it to the conduction band) then the excess energy is lost as heat. In silicon solar panels, half of the solar energy that hits the solar panel is lost due to these two processes. Ideally you would like to somehow harvest the energy that is lost as heat, in order to make solar cells more efficient.
Solar power can also be generated by a thermionic energy convertor, which directly converts heat into electricity. A thermionic converter produces electricity by causing a heat-induced flow of electrons from a hot cathode across a vacuum gap to a cooler anode. However, only a small fraction of the electrons gain sufficient thermal energy to generate this kind of electricity, and very high temperatures are needed for efficient thermionic conversion.
The Stanford researchers have recently developed a new process that exploits the benefits of both solar and thermal cell conversion. The research was led by Nicholas Melosh, as a joint venture of Stanford and SLAC National Accelerator Laboratory. Melosh’s group coated a piece of semiconducting material with a thin layer of metal cesium, demonstrating that this allowed the material to use both light and heat to generate electricity. This new PETE (photon-enhanced thermionic emission) device used the same basic architecture as a thermionic converter except with this special semiconductor as the cathode.
Although the physical process of this PETE device is different than the standard solar cell mechanisms, the new device gives a similar response at very high temperatures. In fact, the PETE device is most efficient at over 200 C. This means that PETE devices won’t replace rooftop solar panels, since they require higher temperatures to be efficient. Instead, they could be used in combination with solar concentrators as part of a large scale solar power plant, for instance in the Mojave Desert.
Melosh’s initial “proof of concept” research was performed with the semiconductor galium nitride to demonstrate that the new energy conversion process works, but galium nitride isn’t suitable for solar applications. They plan to extend their research to other semiconductors, such as gallium arsenide which is commonly used in household electronics. Based on theoretical calculations, they expect to develop PETE devices that operate with a 50 percent efficiency at temperatures exceeding 200 C. They hope to design the new PETE devices so they can be easily incorporated into existing solar power plants, significantly increasing the efficiency of solar power to make it competitive with oil.