Climate Change – Science Sushi

Livestock Infected with Worms Belch and Fart 33% More Methane

Scientists find that parasites dramatically alter how much methane a sheep emits.

It’s estimated that 40% of greenhouse gas emissions come from agriculture, and a substantial portion of that is directly ’emitted’ by livestock. And just last year, climate scientists reported that we’ve actually been underestimating the extent to which the combined belches and flatulence of farmed animals contributes to climate change by 11%. Unsurprisingly, there’s been renewed interest in reducing those emissions, especially considering the demand for livestock is only growing. Now, scientist from the UK report one thing that will help: keep the animals parasite-free.

Continue reading “Livestock Infected with Worms Belch and Fart 33% More Methane”

African Wild Dogs Can’t Take The Heat, Face Extinction From Climate Change

New study suggests African wild dogs may be doomed by climate change. Photo by Mathias Appel

Things aren’t looking good for Africa’s iconic wildlife. Already, many species are threatened by human activities and habitat loss. Even species once thought to be resilient, like giraffes, are suddenly struggling. Just earlier this week, scientists reported that aardvarks, one of sub-saharan Africa’s most successful and adorable insect-eaters and essential ecosystem engineers—face severe declines and even extinction as rising temperatures and declining rainfall dry out the continent. Now, a new paper in the Journal of Animal Ecology adds African wild dogs to the growing list of species that may be eradicated by our changing climate.

Continue reading “African Wild Dogs Can’t Take The Heat, Face Extinction From Climate Change”

Acidifying Oceans Favor Sea Vermin

A common triplefin, one of the fish species that may dominate acidic temperate habitats in the near future. Photo c/o Wikimedia — A common triplefin, one of the fish species that may dominate temperate habitats in the near, acidic future. Photo c/o Wikimedia

Scientists predict that in the next twenty years, the amount of carbon dioxide (CO₂) in our atmosphere will rise from the roughly 404 ppm it is now to over 450 ppm—and as a result, ecosystems worldwide will change. Many impacts will be particularly felt in our planet’s oceans. As atmospheric CO₂levels rise, more of the gas dissolves into our seas, causing a chemical chain reaction which makes the water more acidic. Acidification can act independently or synergistically with rising temperatures, impacting different species in different ways. In a desperate rush to conserve species, scientists are racing against the clock to understand how marine habitats and the species that live in them will be affected by acidification and identify the best ways to retain our marine biodiversity going forward.

The bulk of the research on acidification to date has focused on reef-building corals, and rightfully so, as these reef-producing species are the foundation of some of the richest ecosystems on Earth. But reefs aren’t the only prolific habitats in the sea, and corals certainly aren’t the only species that changing water chemistry will affect. Lab-based studies have found that all kinds of organisms, including fish, are sometimes affected by acidified waters, but how these individual impacts on species translates to ecosystem-level effects is less clear. So to understand how acidification might impact fish communities, a team of scientists led by Professor Ivan Nagelkerken, a marine ecologist in the University of Adelaide’s Environment Institute, turned to natural laboratories. Continue reading “Acidifying Oceans Favor Sea Vermin”

The Summer One Third of the Great Barrier Reef Died

Researchers survey bleached corals in the shallow water in Cygnet Bay, Western Australia, during current bleaching event. Photo Credit: Chris Cornwall

April marked the twelfth consecutive month of record-breaking temperatures. That’s an entire year of our planet, on land and in the sea, being hotter-than-ever-recorded since record keeping began in 1880. Such extraordinary warmth is affecting ecosystems globally, but perhaps the hardest hit are coral reefs, whose fundamental organisms are incredibly sensitive to the heat.

Earlier this year, authorities in Australia reported that the Great Barrier Reef was in the midst of its worst bleaching event ever. Surveys above and below the water estimated that over 90% of the reefs were affected by bleaching. Now, as the summer wanes down under, scientists are finally able to begin to assess the lasting damage caused by this event. Their findings are heartbreaking. Continue reading “The Summer One Third of the Great Barrier Reef Died”

Reef “Cat Scans” Reveal Another Way Acidification Speeds Erosion

Reefs are built by so much more than coral! Photo by — The stunning biodiversity of a “coral” reef. Photo by Laura D

Rising carbon dioxide levels in our atmosphere are changing Earth’s climate at an unprecedented rate. Not only is our planet getting warmer on average—in the oceans, a chemical reaction spurred by dissolved CO2 is altering water chemistry, causing a decrease in pH. This effect of climate change, called ocean acidification, can dissolve the calcium carbonate foundations of coral reefs and other calcifying organisms, making it impossible to build and maintain healthy reefs. Luckily, recent studies on how corals react to lower pHs has given scientists hope that they may be more resilient than previously thought. However, to truly understand how reefs will respond to climate change, we have to look at more than just corals.

Reefs are complex ecosystems, the bases of which are comprised of so much more than corals. There are other species which act as calcifiers, adding to the carbonate foundation (such as crustose coralline algae). The contribution of these non-coral species to reef growth, called secondary accretion, helps shape the surface and guide the settlement of larval corals. There are also species that eat away at the reef, including many worms and sponges. These bioeroders can weaken reef structures until they crumble apart. Whether a reef grows or shrinks over time depends on the interplay between its corals, other reef-builders, and the burrowing organisms which eat their way through the reef’s carbonate foundation. Continue reading “Reef “Cat Scans” Reveal Another Way Acidification Speeds Erosion”

Another Reason To Act Now On Climate Change: Snakes

beware_rattlesnakes

Though scientists have been warning about the disastrous impacts that climate change will have on our planet for decades, we are now starting to feel those predictions manifest. As Eric Holthaus pointed out, the “worst nightmare” scenarios are already happening. Droughts, storms, fires, you name it—the world as we knew it is under siege. Heck, we just had the most abnormally hot month on record; February 2016 was 1.35 degrees Celsius warmer than the average, making it two-tenths of a degree more unusually warm than the previous record month: January 2016.

And as water supplies dwindle, rainforests burn, and corals bleach, we may have yet another thing to worry about: frickin’ snakes.

Continue reading “Another Reason To Act Now On Climate Change: Snakes”

Build it up or let it drown: future prospects for a disappearing nation

This is a guest post by Jamie M. Caldwell, PhD Candidate at the University of Hawai’i at Manoa with the Hawai’i Institute of Marine Biology and NASA Earth and Space Science Fellow. I invited her to write this post for her perspective on the ongoing discussions at COP21 in France, as she was in the Marshall Islands this past June to teach climate science to high school teachers.

For many people, the idea of setting up shop thousands of miles from anywhere on a remote Pacific island, surrounded by palm trees and crystal blue water, sounds like a dream come true. In reality however, life on many of these islands, especially the low elevation islands, is anything but paradise. While developed countries shouldn’t expect to feel the effects of climate change for another 20-30 years, low elevation islands sprinkled across the Pacific Ocean are feeling the effects of climate change today.

“It’s not hard to imagine these islands underwater when you’re standing on a sliver of land with a seemingly never-ending blue ocean on both sides.”

Continue reading “Build it up or let it drown: future prospects for a disappearing nation”

White Hot Insects: Climate Change Leading to Lighter Colors

Pieris_mannii — Lighter wins as climate warms: this butterfly, the Southern Small White (*Pieris mannii*), has continuously expanded its range northwards during the past ten years. Image c/o Nature Communications

Most of the discussion on climate change focuses on startling images of potential loss: the city of Miami underwater due to rising sea level or the lone polar bear on an ever-shrinking iceberg. But some of the greatest impacts of our continued inability to curb our carbon appetite are surprisingly small—little changes that may ultimately have big implications. It’s the butterfly effect—except, in this case, I literally am talking about butterflies. Continue reading “White Hot Insects: Climate Change Leading to Lighter Colors”

Is Climate Change To Blame For This Year’s West Nile Outbreak?

According to the Centers for Disease Control, there have been over 1100 reported cases of West Nile virus disease in the US this year, including 42 deaths. If these numbers seem high, they are – in fact, it’s the highest number of reported cases since West Nile was first detected in the US in 1999, and West Nile season has just begun. Given that the peak of West Nile epidemics generally occurs in mid August, and it takes a few weeks for people to fall ill, the CDC expects that number to rise dramatically. But why now?

Though the CDC doesn’t have an official response to that question, the director of the CDC’s Vector-Borne Infectious Disease Division said that ‘unusually warm weather’ may be to blame. So far, 2012 is the hottest year on record in the United States according to the National Climatic Data Center, with record-breaking temperatures and drought a national norm. It’s likely no coincidence that some of the states hit hardest by West Nile are also feeling the brunt of the heat. More than half of cases have been reported from Texas alone, where the scorching heat has left only 12% of the state drought-free. Fifteen heat records were broken in Texas just last week on August 13th.

The heat waves, droughts and other weather events are the direct effects of climate change say leading scientists. As NASA researcher James Hansen explained in a recent Washington Post editorial, “our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.” He says that the European heat wave of 2003, the Russian heat wave of 2010 and catastrophic droughts in Texas and Oklahoma last year are all the repercussions of climate change. Confidently, he adds that “once the data are gathered in a few weeks’ time, it’s likely that the same will be true for the extremely hot summer the United States is suffering through right now.”

The fact that the worst US West Nile epidemic in history happens to be occurring during what will likely prove to be the hottest summer on record doesn’t surprise epidemiologists. They have been predicting the effects of climate change on West Nile for over a decade. If they’re right, the US is only headed for worse epidemics.

What Is West Nile Virus?

To understand the connection between climate change and disease, you first have to understand West Nile. First discovered in Uganda in 1937, it is what epidemiologists call a zoonotic disease, that is, one that is transmitted from animals to humans, not from humans to humans. West Nile virus mainly infects birds, which are the virus’ true hosts. We humans (as well as livestock and other animals) are accidental casualties of a bird-mosquito disease. West Nile travels via mosquitos that pick up virus particles when they bite infected birds. These particles stay in the mosquito’s salivary glands, and are transmitted into the next host when the mosquito feeds. Humans and other mammals don’t have high enough numbers of viruses in their blood for mosquitos to pick up the infection from them, which is why we are considered “dead end hosts”.

As anyone who hangs out outdoors is aware, mosquito populations pick up in the summer, when environmental conditions are just right for feeding and breeding. So, too, does West Nile. Though it sounds scary, West Nile is a fairly mild infection. Around 80% of people infected show no symptoms at all. Most of the remaining 20% will present with fever, headache and body aches, and nausea which can last for a few days or several weeks, much like getting the flu. Of course, like any illness, West Nile has the potential to be very serious. Less than 1% of infections result in a condition called West Nile meningitis or encephalitis, where the virus infects the spinal cord and even brain. Severe symptoms include high fever, headache, neck stiffness, a decreased level of consciousness (sometimes approaching near-coma), tremors, convulsions, weakness, numbness and paralysis. West Nile meningitis or encephalitis can last several weeks, and the neurological effects can be permanent. As with the flu, the elderly and anyone with a compromised immune system is at a higher risk of severe symptoms and death.

Currently there are no vaccines or antivirals with which to prevent and control West Nile virus in humans. The best offense in the case of West Nile is a good defense. To protect against illness, don’t get bitten by mosquitos in the first place. Wear protective clothing, use nets and screens, and wear insect repellent whenever you are in an area where people have gotten sick. The CDC has updated maps on where cases have occurred, though if you’re unsure if your area is suspect, caution is better than regret. Of course, if you look at that map, only one state has no West Nile activity: congrats, Vermont, on so far eluding the epidemic.

Turning Up The Heat

Higher temperatures bolster the chances of infection on many fronts. Temperature has a profound effect starting at the source: the mosquito. Studies have found that mosquitos pick up the virus more readily in higher temperatures. Higher temperatures also increase the likelihood of transmission, so the hotter it is outside, the more likely a mosquito that bites an infected bird will carry the virus and the more likely it will pass it along to an unwitting human host. In the United States, epicenters of transmission have been linked closely to above-average summer temperatures. In particular, the strain of West Nile in the US spreads better during heat waves, and the spread of West Nile westward was correlated with unseasonable warmth. High temperatures are also to blame for the virus jumping from one species of mosquito to a much more urban-loving one, leading to outbreaks across the US.

Though you might think that the droughts associated with heat waves would slow down mosquitos, it turns out to be the exact opposite. That’s because the main mosquito now involved in West Nile transmission, city-loving Culex pipiens, actually thrives in drought conditions. C. pipiens tends to breed underground in water that sits in city drains. During a drought, these pools become rich in organic material that C. pipiens needs to survive, whereas rainfall flushes the drains and dilutes the nutrients in the standing pools. Drought also has a negative effect on C. pipiens’ predators like frogs and dragonflies – and where there are less predators, there are more mosquitos. To add to the problem, drought tends to cause birds to cluster around water resources, making them easy pickings for hungry mosquitos and upping transmission rates.

The Real Inconvenient Truth

I can’t sum it up any better than Paul Epstein did in his 2001 review of climate change and West Nile:

“We have good evidence that the conditions that amplify the life cycle of the disease are mild winters coupled with prolonged droughts and heat waves—the

long-term extreme weather phenomena associated with climate change.”

While some politicians are hesitant to accept the scientific consensus of climate change, West Nile is more than happy to reap the rewards of our poor environmental choices. It’s not the only disease benefitting from our flagrant CO2 emissions; epidemiologists predict that many vector-borne diseases, including deadly ones like malaria and dengue fever, will increase in incidence world wide as global temperatures rise.

While the CDC is hesitant to blame this year’s West Nile outbreak on climate change directly, the science is clear. Record-breaking incidences of West Nile are strongly linked to global climate patterns and the direct effects of carbon dioxide emissions. Climate change isn’t just going to screw with the environment, it will continue to have devastating public health implications. In addition to better mosquito control and virus surveillance, we need to focus our efforts on reducing and reversing climate change if we want to protect our health and our well-being.

Image credits: Disease collage by Visual Mozart / purchased from ImageZoo; Transmission cycle image from the CDC website; mosquito danger image from petrafler / 123RF Stock Photo