Climate change associated with antibiotic resistance


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E. coli bacteria is a common cause of urinary tract infections and has shown resistance to antibiotics. (National Institute of Health/flickr)

Jenna Ladd | May 25, 2018

The human health impacts of climate change are myriad and include heat-related illnesses and vector borne diseases like Lyme disease. However, a new public health consequence of global warming has recently come to light: antibiotic resistance.

Earlier this week, a study published in the journal Nature Climate Change reported finding that higher local temperatures and population densities are associated with increased antibiotic resistance of common pathogens. Researchers looked at 1.6 million bacterial specimens which showed resistance to antibiotics from 2013 through 2015 in various geographic locations in the U.S. These specimens included three common and deadly pathogens: Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. 

They found that a temperature rise of 10 degrees Celsius increased the bacterias’ resistance to antibiotics by four percent (E. coli), two percent (K. pneumoniae), and three percent (S. aureus). John Brownstein is a professor of medicine at Harvard Medical School and one of the study’s authors. He said to the Scientific American, “Places in the South [of the U.S.] tend to show more resistance than places in the North, and a good chunk of that variability can be explained by temperature.”

Researchers also explored how population density may be related to antibiotic resistance. They found that for every increase of 10,000 people per square mile, antibiotic resistance in that area increased by three to six percent. Prior to this study, most research about antibiotic resistance pointed to the overprescription of antibiotic medication as the primary reason for antibiotic resistance, but now, climate change and population density are known play a part.

The study concludes, “Our findings suggest that, in the presence of climate change and population growth, already dire predictions of the impact of antibiotic resistance on global health may be significant underestimates.”

Warmer temperatures make milkweed toxic for monarchs


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A monarch caterpillar scoots across a common milkweed leaf. (USFWSmidwest/flickr)

Jenna Ladd | April 6, 2018

A recent study published in the journal Ecology uncovered an unexpected consequence of climate change for monarch butterflies.

Researchers from Louisiana State University and University of Michigan set out to understand how warmer temperatures affect the relationship between monarch butterflies and milkweed plants. The insects, whose population has declined by more than 80 percent in the last decade, lay their eggs exclusively on milkweed plants. After the larvae hatch, they feed on certain species of milkweed, which provide protection to the butterflies. Milkweed plants produce chemicals called cardenolides in their leaf tissues, which are poisonous to most of the monarch’s predators. When monarchs consume the perfect amount of these chemicals as larvae, it sends a signal to larger predators to stay away from them.

However, scientists found that as regional temperatures rise, some species of milkweed plants produce more cardenolides. This poses a threat to the monarchs’ survival. One of the researchers, Dr. Bret Elderd, an associate professor at Louisiana State University, explained, “It’s a Goldilocks situation for monarch butterflies. Too few of these chemicals in the milkweed, and the plant won’t protect monarch caterpillars from being eating. But too high of a concentration of these chemicals can also hurt the monarchs, slowing caterpillar development and decreasing survival.”

One species of milkweed by the Latin name of A. curassavica has naturally high levels of cardenolides in its leaves and is especially sensitive to rising temperatures. Landscapers and environmentalists alike have been planting more of the nonnative plant to save the monarchs, but scientists warn that this plan may have backfired. They are working to spread the word that the native variety of milkweed, A. incarnata, has naturally lower levels of cardeolides and is much less likely to become toxic to monarchs as the climate warms.

The study reads, “It has become increasingly recognized that species interactions, especially interactions between tightly-linked species, need to be considered when trying to understand the full impacts of climate change on ecological dynamics.”

The full report can be found here.

U.S. residents increasingly divided on climate change


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A Gallup graph depicts how opinions about climate change have changed over time in the U.S. (Gallup)

Jenna Ladd | March 29, 2018

A recent poll found that Americans have become even more polarized about climate change in the last year. Gallup completed the poll during the first week of March using a random sample of 1,041 adults in the United States.

While concern about global warming is still at a record high, the difference in opinions between Republicans and Democrats is now more stark. The poll found that 69 percent of Republicans thought that the seriousness of climate change is generally exaggerated in the news, while just four percent of Democrats believed the same thing. Similarly, just over 40 percent of Republicans said that they believe the undisputed fact that nearly all scientists believe that global warming is taking place, while 86 percent on Democrats did.

Gallup hypothesized about the increased polarization in opinion between the parties. They wrote,

“President Donald Trump, who has called global warming a “hoax,” may have contributed to this widening divide by reversing a number of government actions to address the issue. These included the announcement that the U.S. will withdraw from the 2015 Paris climate accord, the removal of climate change from the list of top U.S. national security threats and the elimination of the terms “global warming” and “climate change” from U.S. government websites and lexicons.”

Despite evidence that the number of severe weather-related deaths has risen because of climate change, few members of the Republican party seemed to think that climate change would pose a serious in their lifetime. Just 18 percent said that there was any real risk to them.

This year, Gallup has categorized about 48 percent of U.S. citizens as concerned believers in climate change, which is similar to 2017’s 50 percent figure. About 32 percent have mixed opinions about the existence and cause of climate change, and 19 percent are categorized as climate change skeptics.

Carbon emissions on the rise after years of stagnation


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Carbon emissions increased in 2017 for the first time in years. (Sunny Vhaii/flickr)
Jenna Ladd | March 22, 2018

Global carbon emissions were higher than ever in 2017 according to Global Energy and CO2 Status Report from the International Energy Agency (IEA) based in Paris.

Carbon emissions reached a record 32.5 giggatons last year after remaining stable for the three previous years. This figure can be thought of as putting 170 million additional cars on the road. The spike in carbon emissions has been attributed to two factors. First, global energy demand increased by 2.1 percent last year. This is double the average 0.9 percent increase over the previous five years. About seventy percent of this demand was met by emission producing fossil fuels like oil, natural gas and coal. Second, energy efficiency improvements slowed down during 2017.

“The significant growth in global energy-related carbon dioxide emissions in 2017 tells us that current efforts to combat climate change are far from sufficient,” Fatih Birol, IEA’s executive director, said to Reuters. He continued, “For example, there has been a dramatic slowdown in the rate of improvement in global energy efficiency as policy makers have put less focus in this area.”

Scientists say the carbon emissions need to peak soon and then decrease dramatically by 2020 in order to meet the international climate goal of keep average global temperature rise lower than 2 degrees above pre-industrial levels.

Although carbon emissions increased most places, the United States, United Kingdom, Mexico and Japan all saw reductions in carbon emissions. Surprisingly, U.S. carbon emissions fell by 0.5 percent, more than any other country.

Allergy season longer because of climate change


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Pollen from ragweed is a common allergen for people with seasonal allergies. (Stacey Doswell/flickr)
Jenna Ladd | March 21, 2018

Tuesday was the first day of spring, but that is not good news for everyone. Last year was the worst year for seasonal allergies and experts expect this year to bring more of the same. Climate change is allowing for pollen-producing plants to bloom early and stay alive longer as warmer seasons grow in length.

Allergen and pollen counts are skyrocketing and the length of allergy season is growing around the country thanks to higher average temperatures. Since 1995, the length of ragweed allergy season in Iowa has increased by 15 days according to the Environmental Protection Agency.

The Center for Disease Control reports that more than 50 million U.S. citizens now have seasonal allergies each year, and that number is growing. Medical experts have reported that many people are beginning to suffer from seasonal allergies for the first time during adulthood. Allergy symptoms can range from itchy eyes and sneezing to potentially life-threatening anaphylactic shock. It is estimated that these symptoms cost the U.S. healthcare system $3.4 billion and $11.2 billion every year in direct medical expenses, and keep many Americans home from work.

Dr. Joseph Shapiro, an allergist and immunologist from California told CBS news, “A recent study showed that pollen counts are likely to double by the year 2040, so in a little more than 20 years we’re going to see a significant increase [in seasonal allergies].”

More common and intense seasonal allergies are just one of the human health consequences of climate change. Studies have shown that U.S. residents can also expect increased incidences of heat-related illness, higher risk for diseases from vectors like ticks and respiratory complications related to poor air quality. A complete map of climate change’s effect on human health in specific regions of the U.S. can be found here.

Record high winter temperatures in Arctic, again


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The Rink Glacier in Greenland captured melting into the sea during the summer of 2012. (NASA/Flickr)
Jenna Ladd | March 8, 2017

The data is in, and winter temperatures in the Arctic reached record highs again this year.

U.S. weather data shows that average temperatures during December, January, and February this year were 8.8 degrees Fahrenheit warmer than usual. There are fifteen weather monitoring stations throughout the Arctic, many of them in Alaska and Greenland. Winter temperatures in some regions soared higher than the average. Barrow, Alaska, for example, sizzled with average winter temperatures a full 14 degrees Fahrenheit above normal.

Even the weather monitoring station that is located closest to the top of the world in northern Greenland recorded 60 hours of above freezing temperatures this winter. Prior to this winter, scientists say, the station had only experienced above-freezing temperatures during February a few times in history.

The rising temperatures caused sea ice to vanish in the North Pole again this year. North Pole sea ice coverage hit a record low in February 2017 and decreased again this year by a full 62,000 square miles, which is about the size of the state of Georgia.

Ruth Mottram is a climate scientist at the Danish Meteorological Institute. She said to the Associated Press, “The extended warmth really has kind of staggered all of us.”

Some scientists have pointed to melting sea ice as an explanation for the extreme and strange winter weather that has plagued the eastern United States this year. Simply put, less sea ice means that there is less of an atmospheric pressure difference between the Arctic and areas further south, which weakens the jet stream. A weak jet stream causes  storms to linger over regions in the eastern U.S. and Europe before moving along, often making them more destructive.

Women more likely to be affected by and act on climate change


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Women and children are most susceptible to heat-related illnesses that are becoming more common due to climate change. (Janet Mailbag/flickr)

Jenna Ladd | February 8, 2018

During a recent speech at Georgetown University, former Secretary of State Hillary Rodham Clinton pointed out that women are disproportionately affected by climate change worldwide.

Research from several sources back up this claim. Discussing global desertification due to drought and intense heat waves, Clinton said, “I would say that particularly for women…they will bear the brunt of looking for the food, looking for the firewood, looking for the place to migrate to when all of the grass is finally gone.”

The gendered effects of climate change extend beyond communities in developing nations, however. Researchers from the Natural Resources Defense Fund point out that two-thirds of those jobs lost after Hurricane Katerina in New Orleans were lost by women. Job creation during the rebuilding periods following natural disasters are primarily in the construction industry and go almost exclusively to men. As a result, 83 percent of single mothers were not able to return to New Orleans following the hurricane.

The changing climate poses unique risks to women’s health as well. Increasingly frequent and intense heat waves can cause low birth weights among pregnant women. Women are also fourteen times more likely to die during a natural disaster than men. Researchers link this to insufficient access to information and warnings as well as a difference in women’s ability to cope with such events.

As Clinton put it, women “bear the brunt” of a changing climate. Perhaps that’s why women in political positions of power are more likely than their male counterparts to sign off on treaties that combat climate change.

Perrin Ireland is a science reporter for the Natural Resources Defense Fund. She said, “Women play critical roles in our communities, and our voices must be heard for climate action. In order to have a resilient future, for the thriving of our communities, women must have a seat at the table.”