Day: May 5, 2021

How cleaning up coolants can cool the climate – why HFCs are getting phased out from refrigerators and air conditioners

HFCs keep refrigerators cool, but their leaks are warming the planet. Jed Share/Kaoru Share via Getty Images

by Scott Denning (Colorado State University)

The U.S. Environmental Protection Agency is moving to eliminate a class of chemicals widely used as coolants in refrigerators, air conditioners and heat pumps.

If that feels like déjà vu, it should.

These chemicals, called hydrofluorocarbons, or HFCs, were commercialized in the 1990s as a replacement for earlier refrigerants that were based on chlorofluorocarbons, or CFCs. CFCs were destroying the ozone layer high in the Earth’s atmosphere, which is essential for protecting life from the sun’s harmful ultraviolet radiation.

HFCs are much less harmful than CFCs, but they create another problem – they have a strong heat-trapping effect that is contributing to global warming.

Several states have announced plans over the past few years for phasing out HFCs. Now the EPA, following a vote in Congress, is proposing federal regulations to cut HFC production and imports starting in 2022, and aims to reduce their production and use by 85% within 15 years.

Let’s take a closer look at what HFCs are and what might replace them next.

How HFCs keep rooms and food cool

Refrigerators and air conditioning use a technology known as a heat pump. It sounds almost miraculous – heat pumps use energy to take heat out of a cold place and dump it in a warm place.

Here’s how a refrigerator works: A fluid – CFCs back in the old days, and now HFCs – circulates in the walls of the refrigerator, absorbing the ambient heat to keep the fridge cooled down. As that liquid absorbs the heat, it evaporates. The resulting vapor is pumped to the coils on the back of the refrigerator, where it is condensed back to a liquid under pressure. In the process, the heat that was absorbed from inside the fridge is released into the surrounding room. Air conditioners and home heat pumps do precisely the same thing: they use electric-powered compressors and evaporators to move heat into or out of a house.

How a refrigerator works.

Choosing the right fluid for a refrigerator means finding a substance that can be evaporated and condensed at the right temperatures by changing the pressure on the fluid.

CFCs seemed to fit the bill perfectly. They didn’t react with the tubing or compressors to corrode the equipment, and they weren’t toxic or flammable.

Unfortunately, the chemical stability of CFCs turned out to be a problem that threatened the whole world, as scientists discovered in the 1980s. Leaking CFCs, mostly from discarded equipment, remain in the atmosphere for a long time. Eventually they make their way to the stratosphere, where they are finally destroyed by UV radiation from the sun. But when they break down, they create chlorine that reacts with the protective ozone, letting dangerous radiation through to the Earth’s surface.

When production of CFCs was eliminated in the 1990s to protect the ozone layer, new refrigerants were developed and the industry shifted to HFCs.

Why HFCs are a climate problem

HFCs are like CFCs but much more reactive in air, so they never reach the stratosphere where they could harm Earth’s protective radiation shield. They largely saved the world from impending ozone disaster, and they are now found in refrigerators and heat pumps everywhere.

But while HFCs’ chemical reactivity prevents them from depleting the ozone layer, their molecular structure allows them to absorb a lot of thermal radiation, making them a greenhouse gas. Like carbon dioxide on steroids, HFCs are extremely good at capturing infrared photons emitted by the Earth. Some of this radiant energy warms the climate.

Unlike CO2, reactive HFCs are consumed by chemistry in the air, so they only warm the climate for a decade or two. But a little bit goes a long way – each HFC molecule absorbs thousands of times as much heat as a CO2 molecule, making them powerful climate pollutants.

Chart showing increase by country, with the largest increase in China.
HFC emissions are increasing. The chart shows their anticipated growth without control measures in place. Netherlands National Institute for Public Health and the Environment

HFCs leaking from discarded cooling equipment are estimated to contribute about 4% of global greenhouse gas emissions – about twice as much as aviation.

This is why it’s time to retire HFCs and swap them out for alternative refrigerants. They’ve done their job saving the ozone layer, but now HFCs are a major contributor to short-term global warming, and their use has been increasing as demand for cooling increases around the world.

What can replace HFCs?

Because they are so powerful and short-lived, stopping the production and use of HFCs can have a significant cooling effect on the climate over the next couple of decades, buying time as the world converts its energy supply from fossil fuels to cleaner sources.

The good news is that there are alternative refrigerants.

Ammonia and hydrocarbons like butane evaporate at room temperature and have been used as refrigerants since the early 20th century. These gases are short-lived, but they have a downside. Their greater reactivity means their compressors and plumbing have to be more corrosion-resistant and leak-proof to be safe.

Rows of freezer cases in a store.
Designing refrigeration equipment for different chemicals will likely mean retooling the industry, which could raise costs. Mint Image via Getty Images

The chemical industry has been developing newer alternatives intended to be safer for both people and climate, but as we saw with CFCs and HFCs, inert chemicals can have unintended consequence. Several industry leaders have supported efforts to phase out HFCs, including the Kigali Amendment – an international agreement to globally reduce HFC use that was signed in 2016 but has yet to be ratified by the U.S.

So, it’s time for another generation of cooling equipment. Just as our TVs and audio equipment and light bulbs have evolved over past decades, our refrigerators and air conditioners will be replaced by a new wave of improved products. New refrigerators will look and work just like the ones we’re used to, but they will be much gentler on the climate system.

Scott Denning, Professor of Atmospheric Science, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Solar city? Turning buildings into power plants

Read the full story in Forbes.

Developments from research labs and the renewables sector are driving new trends in urban design

Assessing and selecting sustainable leaders

Read the full story from Russell Reynolds Associates.

Russell Reynolds Associates recently partnered with the United Nations Global Compact to study the characteristics and behaviors that differentiate sustainable business leaders from other top-tier executives, the findings of which were summarized in our joint whitepaper Leadership for the Decade of Action. The article below builds upon this research to focus on the question of assessing and selecting sustainable leaders in the hiring process. Please refer to the original study for full details on methodology and findings.

Environmental DNA – how a tool used to detect endangered wildlife ended up helping fight the COVID-19 pandemic

Looking for bits of DNA at the University of Florida. David Duffy, CC BY-ND

by Jessica Alice Farrell & David Duffy (University of Florida) and Liam Whitmore, (University of Limerick)

Imagine discovering an animal species you thought had gone extinct was still living – without laying eyes on it. Such was the case with the Brazilian frog species Megaelosia bocainensis, whose complete disappearance in 1968 led scientists to believe it had become extinct. But through a novel genetic detection technique, it was rediscovered in 2020.

Such discoveries are now possible thanks to a new approach that recovers and reads the trace amounts of DNA released into the environment by animals. It’s called environmental DNA, or eDNA – and it takes advantage of the fact that every animal sheds DNA into its environment via skin, hair, scales, feces or bodily fluids as it moves through the world.

As wildlife biologists at the University of Florida’s Whitney Laboratory for Marine Bioscience & Sea Turtle Hospital, we use eDNA to track a virus responsible for a sea turtle pandemic called fibropapillomatosis, which causes debilitating tumors. We also use eDNA to detect sea turtles in the wild.

But in 2020, human health researchers began repurposing eDNA techniques to track the COVID-19 pandemic. This is a prime example of how research in one area – wildlife conservation – can be adapted to another area – human disease mitigation. Going forward, we believe eDNA will prove to be an essential tool for monitoring both human and animal health.

From soil microbes to sea turtles

Scientists in the 1980s began hunting for microbe DNA in soil samples. Over the next 20 years, the technique was adapted for use with air and water samples, and scientists started using eDNA to detect larger animals and plants.

A flowchart of how snow/ice, freshwater, soil, sand or seawater samples can be collected and analyzed for their DNA.
Scientists now can detect DNA traces from many different environments. Liam Whitmore, University of Limerick, CC BY-ND

While the science behind eDNA techniques is complex, the actual process of collecting and testing a sample is relatively simple. Samples are filtered through very fine paper, which traps loose cells and strands of DNA. The techniques to read what DNA is present are the same as those used for tissue or blood samples, usually quantitative polymerase chain reaction or whole genome sequencing. Scientists can either read all of the DNA present from every organism – or target just the DNA from species of interest.

Scientists now routinely use eDNA to detect endangered wildlife and invasive species. The ability to tell whether an animal is present without ever needing to lay eyes or a lens on it is an incredible leap forward, decreasing the time, resources and human effort needed to monitor and protect vulnerable species.

A sea turtle on its back in an exam room. One of its flippers is severely deformed.
Routine imaging of a juvenile green sea turtle patient afflicted with virus-triggered fibropapillomatosis at the Florida Whitney Sea Turtle Hospital. Devon Rollinson-Ramia, CC BY-ND

However, to truly protect endangered species, it’s not just the animals that need to be monitored, but the pathogens that threaten their survival. Environmental DNA is able to monitor the parasites, fungi and viruses that can cause disease in wildlife.

Tracking COVID-19

While scientists originally applied eDNA to human pathogen detection over a decade ago, it wasn’t until the beginning of the current COVID-19 human pandemic that the repurposing of eDNA took off on a large scale, allowing the technology to make staggering advancements in very short order.

Coronavirus genomes consist not of DNA, but rather its cousin molecule, RNA. So researchers have rapidly optimized a variation of eDNA – eRNA – to detect coronavirus RNA in air and human wastewater.

For example, at the University of Florida Health Shands Hospital, researchers collected air samples from the hospital room of two COVID-19 patients. Using eRNA, they successfully isolated and sequenced the virus. Confirming air as a key route of transmission directly influenced public health guidelines.

A gloved hand holds a sealed plastic bottle of murky-looking water.
Collecting sewage samples to test for SARS-CoV-2 at Utah State University in September 2020. AP Photo/Rick Bowmer

When scientists apply eRNA to archived wastewater samples, the true dates of SARS-CoV-2 appearance can be detected. SARS-CoV-2 concentration in wastewater in Valencia, Spain, peaked on March 9, 2020, but the number of clinical cases didn’t peak until the start of April 2020 because of the lag time between infection and severe clinical symptoms.

This sort of predictive monitoring has profound implications for health care systems, allowing time to prepare – not just for COVID-19, but for any future disease outbreaks that threaten human populations.

[Understand new developments in science, health and technology, each week. Subscribe to The Conversation’s science newsletter.]

Intersection of diseases

It’s vital that human and animal diseases are studied together. Sixty percent of emerging human pathogens come from animals – with many of these (42%) originating in wildlife populations, including Ebola, Zika, West Nile and Marburg viruses. Alternatively, people can also transmit pathogens to animals.

SARS-CoV-2 has already infected apes at a zoo in San Diego, large cats at a zoo in New York and minks at farms in Europe – the latter of which gave rise to new variants that could prove a new threat to people.

Medics, veterinarians and scientists call this convergence of human, animal and environmental well-being OneHealth or EcoHealth. Studying and treating human and wildlife disease together recognizes their commonalities and often yields breakthroughs.

With eDNA, all pathogens can be monitored in an environment regardless of where they come from. An integrated eDNA monitoring program could cost-effectively provide advanced warning of human, livestock and wildlife diseases.

Jessica Alice Farrell, PhD Candidate in Biology, University of Florida; David Duffy, Assistant Professor of Wildlife Disease Genomics, University of Florida, and Liam Whitmore, PhD Candidate, Department of Biological Sciences, University of Limerick

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate change threatening Illinois’ wildlife, forests, grasslands

Read the full story from ABC7.

The impacts of climate change on wildlife throughout Illinois is already showing up.

Warmer weather, especially in the winter, combined with more frequent heavy rain events, is having a slew of effects on the grasslands, forests and the wildlife of Illinois.

Of all the natural areas in Illinois, 75% is grasslands, this is where we are seeing some of the greatest impacts of climate change.

As climate concerns grow, how is it getting cheaper to finance gas in the US?

Read the full story at Utility Dive.

It appears global financial institutions are beginning to price in the energy transition and associated climate risks — except when it comes to oil and gas. 

That’s a key finding of an important new study released by a team of researchers led by Ben Caldecott at the University of Oxford Smith School of Enterprise and the Environment. Poring over financial transaction data that spans two decades, the team sought to answer a basic question — are financial markets pricing in climate risk? The answer it turns out is not that simple and frankly, a bit disturbing.

Lamb Weston’s Alexia Frozen Potatoes switch to sustainable biomaterial packaging

Read the full story at Refrigerated & Frozen Foods.

Two Lamb Weston Alexia brand frozen potato products will now use corn and potato starch in their packaging. The biodegradable bags are partially made of potato starches, a byproduct of producing French fries, and will be identified with a label on the front of the package indicating it is partially made from plants.

PepsiCo to eliminate 3 million tons of GHGs through regenerative agriculture practices

Read the full story at Environment + Energy Leader.

PepsiCo will eliminate at least three million tons of greenhouse gas emissions by 2030 through a new agenda that will source crops in a way intended to accelerate regenerative agriculture across seven million acres — equal to the amount of land used around the world to grow the ingredients used in the company’s products. The company will work with farmers to adopt practices that build resilience and improve and restore ecosystems, with a goal of sustainably sourcing 100% of its key ingredients by 2030, PepsiCo says.

Cheap, green, and beautiful: The future of housing, according to this year’s Solar Decathlon winners

Read the full story at Fast Company.

The winners of the 2021 Solar Decathlon Build Challenge show how to build energy-efficient housing in extreme climates—the kinds of conditions climate change will only make more prevalent.

Scientists in State Politics

Addressing almost any issue – from facial recognition usage and automated vehicles to wildfires, superstorms and the many ramifications of pandemics – requires policymakers at all levels of government to quickly make critical decisions that are informed by increasingly complex scientific data and understanding.

With this database, the Eagleton Science and Politics Initiative presents the first iteration of a publicly accessible national inventory of elected state legislators with scientific, engineering and healthcare training.

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