Climate Change, Conservation, Nature

Old Nautical Charts Reveal Coral Loss

British navigation charts from the 1800s show us how much coral has disappeared.
British navigation charts from the 1800s show us how much coral has disappeared. Photo: Shutterstock

Nautical charts mapped in the 18th century are showing modern researchers just how much coral has been lost around the world.

A new U.S. and Australian study has compared early British navigation charts to modern coral habitat maps to determine what changes have taken place over the past three centuries.

The study was led by Professor Loren McClenachan of Colby College in Waterville, Maine, with assistance from the University of Queensland (UQ) in Australia and the Australian Research Council Centre of Excellence in Coral Reef Studies.

Professor John Pandolfi of UQ said that the study used information from “surprisingly accurate” 18th century nautical charts and satellite data to understand coral loss in the Florida Keys.

Professor McClenachan said that more than half of the coral reef habitat mapped in the 1770s was no longer there. In some areas, coral loss was close to 90 percent.

“We found near the shore, entire sections of reef are gone, but in contrast, most coral mapped further from land is still coral reef habitat today,” McClenachan said.

This is one of the first studies where marine scientists have measured the loss of coral reef habitats over a large geographic area. Most studies look more closely at the loss of living coral from smaller sections of reefs.

“We found that reef used to exist in areas that today are not even classified as reef habitat anymore,” Pandolfi said. “When you add to this the 75 percent loss of living coral in the Keys at that finer scale, the magnitude of change is much greater than anyone thought.”

Dr. Benjamin Neal of the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine, said that the early maps were remarkably precise.

“They had the best technology and they used it to create new information that conferred a lot of power,” Neal said. “The maps were essential to expansion of the British Empire, and luckily for us, they also included a lot of useful ecological information.”

This research has important conservation implications. As the authors said, when large-scale changes like this were overlooked, scientists could miss out on information about past abundance.

“We tend to focus on known areas where we can measure change. That makes sense. Why would you look for coral where you never knew it was?” McClenachan said.

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Climate Change, Environmental Hazards, Nature, Science

Was Hurricane Harvey Caused by Global Warming? Not Entirely

Was Hurricane Harvey caused by global warming? Not entirely.
Cars submerged by flooding in the wake of Hurricane Harvey. Photo: michelmond / Shutterstock.com

Climate change is responsible for a lot of things, but it may not be directly responsible for Hurricane Harvey.

Harvey is not the first hurricane to hit the Texas coast.  A deadly hurricane struck Galveston in 1900, and that storm caused thousands to lose their lives, primarily due to the lack of warning. Meteorology was not an advanced science at that time, and there were no satellites to track the storms as they moved across the Atlantic Ocean.

However, climate change is almost certainly responsible for the epic rainfall and catastrophic flooding endured by the cities struck by Hurricane Harvey.

“This is they type of event, in terms of extreme rainfall, that we would expect to see more of in a warming climate,” Dr. Friederike Otto from the University of Oxford told the BBC.

In fact, the rainfall was so extreme that the National Weather Service had to add new colors to its rainfall maps to account for the intensity of Harvey’s rains.

There’s a physical law called the Clausius-Claperyon equation, which says that a hotter atmosphere holds more moisture. For every degree Celsius in warming, the atmosphere can hold 7 percent more water, which makes rainfall events more extreme.

The temperature of the seas also contributes to the strength of hurricanes.

“The waters of the Gulf of Mexico are about 1.5 degrees warmer than they were from 1980 to 2010,” Sir Brian Hoskins of the Grantham Institute for Climate Change told the BBC. “This is very significant because it means the potential for a stronger storm is there, and the contribution of global warming to the warmer waters in the Gulf, it’s almost inevitable that there was a contribution to that.”

Although there have been slow-moving storms over Texas in the past, some scientists still attribute the intensity of Harvey to climate change.

Professor Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research says that a general slowdown in atmospheric circulation in the earth’s middle latitudes could be a result of changing climate in other parts of the world.

“This is a consequence of the disproportionately strong warming in the Arctic,” Rahmstorf said. “It can make weather systems move less and stay longer in a given location—which can significantly enhance the impacts of rainfall extremes.”

Other scientists think it’s a stretch to believe that the slowly moving nature of the storm is caused by climate change. “I don’t think we should speculate on these more difficult and complex links like melting in the Arctic without looking into these effects in a dedicated study,” said Dr. Otto.

In addition to the damage caused by the flooding, pollution is causing the floodwaters to become a toxic stew of sewage, garbage, chemicals from more than 20 Superfund sites in the Houston area, oil and petrochemicals from damaged refineries, and much more, are causing concern.

“There’s no need to test [the water],” Houston Health Department spokesman Porfirio Villareal told the New York Times. “It’s contaminated. There’s millions of contaminants.”

Climate Change, Nature, Science

Galápagos Seabird Population May Shrink Due to Global Warming

Nazca boobies and other animals are in jeopardy as water warms around the Galápagos Islands.
A Nazca booby guards her egg. Photo via Pixabay

The Galápagos Islands are the home of thousands of unique species. In fact, those islands were where Charles Darwin began writing about his findings on evolution. But at least one of these species is in jeopardy because of warming ocean temperatures.

Within the next century, rising ocean temperatures around the Galápagos Islands are expected to make the water too warm for sardines to tolerate.

Why is that important? Sardines are a key prey species for many seabirds including the Nazca booby.

Wake Forest University biologists published a study in the August 23 issue of the journal PLOS ONE about this phenomenon. They used decades of data on the diet and breeding of the Nazca booby to understand how the absence of sardines could affect the booby population.

They studied the diet, breeding, and survival of Nazca boobies as part of their study at Isla Españnola in the Galápagos Islands for more than 30 years. In 1997, halfway through their study, sardines disappeared from Nazca booby diet samples, replaced by flying fish.

Flying fish are less nutritious than sardines, and as researcher Emily Tompkins, lead author of the study, said, as flying fish replaced sardines in the birds’ diet, “reproductive success was halved.”

“If the current links between diet and reproduction persist in the future, and rising ocean temperatures exclude sardines from the Galápagos, we forecast the Nazca booby population will decline,” Tompkins said.

David Anderson, a professor of biology and co-author of the study, said, “Few connections have been made between ocean warming and population effects in the tropics, making this study significant.”

But the Nazca booby isn’t the only creature that could be harmed by rising ocean temperatures. The study suggests that other Galápagos predators that do well when sardines are available will have to adjust to a new menu within the next 100 years.

So many species have gone extinct or become highly endangered due to global climate change—probably including species we never even discovered—that it behooves us to act to stop, or at least slow, climate change. Given the United States’ exit from the Paris Climate Agreement, it’s up to other nations, and states and cities within the U.S., to step up and do something about this increasing danger to the survival of all animals, including humans.

Climate Change, Environmental Hazards

Climate Change Bringing Tropical Diseases to Higher Latitudes

Tropical diseases are spreading farther north as the climate continues to warm.
The Anopheles mosquito is responsible for the spread of malaria. Its range may be increasing due to climate change. Photo via Pixabay

It’s been known for a long time—like, since Roman times—that climate change brings disease. Roman aristocrats would move to summer homes in the mountains in order to avoid malaria-transmitting mosquitoes, for example.

But even the appearance of malaria mosquitoes was simply a summer phenomenon that was a regular part of south European climate. Nowadays, we have more to be worried about, thanks to global climate changes.

Tropical diseases like viral illness Chikungunya, West Nile Virus, and Zika; bacterial infection Vibrio vulnificus; and parasitic infection malaria are finding their way farther and farther north as greenhouse gases boost temperatures around the world.

The Asian tiger mosquito and yellow fever mosquitoes infect humans with Chikungunya. The virus had been limited to tropical regions of Africa, Asia, and South America, but as temperatures have warmed, the geographical distribution of these mosquitoes has grown. If climate change continues unchecked, a team at the University of Bayeruth warns, the virus could even spread to southern Europe and the United States.

“People have already been infected with Chikungunya in Italy, France, and Florida,” said Dr. Stephanie Thomas, a biogeography researcher at the University of Bayeruth. “However, such cases are still too rare to play any significant role in our model. The climactic potential for new diseases in southern Europe and the U.S. is probably being underestimated.”

Vibrio illnesses are caused by bacteria that occur naturally in warm ocean waters. Although Vibrio infections have been seen sporadically in warm seas from Texas to Maryland, Vibrio bacteria are spreading north. Vibrio illnesses have even appeared as far north as the Arctic Circle.

We are seeing lots of new hospitable areas opening up for these bacteria,” said Craig Baker-Austin, a Vibrio expert at the UK’s Centre for Environment, Fisheries, and Aquaculture Sciences laboratory in southern England. “Climate change is essentially driving this process, especially warming.”

In Europe, ticks that carry Lyme disease, that once only appeared in southern Europe, are now appearing as far north as Sweden. A region near Russia’s Ural Mountains has seen a 23-fold increase in tick-borne encephalitis over the past 20 years. The sand flies that host the parasite-borne illness leishmaniasis are showing up in north Texas.

“So often so many of the things we talk about with climate change are ‘this is going to be a problem in 2030 or 2050 or 2100, and it sounds so far away,” said Stanley Maloy, a microbiologist at San Diego State University. “But we’re talking about things where our one-degree centigrade change in temperature is already enough to affect infections. We have clear evidence in many cases things are happening already, and they’re tightly correlated to changes in ambient temperature, extreme weather, or water temperature.”

Regardless of whether people believe climate change is real, it’s inevitable that even the greatest skeptics will soon find themselves being affected by the spread of tropical diseases to higher latitudes.

Climate Change, Nature

Scientists Concerned About Rapid Change in Arctic River Ice

Arctic river ice is melting at an accelerating rate.

The Arctic continues to bear the brunt of climate change’s current effects, with new research showing that Arctic river ice is accruing in smaller amounts and melting earlier in the season.

Arctic groundwater comes to the surface and freezes on top of already frozen rivers, and these deposits of ice grow throughout the season until whole river valleys are covered. Some river icings have grown to over 4 square miles, and as deep as 33 feet. Traditionally, they start melting in the middle of July, which keeps many rivers running long after they would otherwise have dried up, and provides fresh water for many different creatures and habitats.

But over the past 15 years, there has been less of that ice forming, and it’s been melting about a month earlier. This means habitats that rely on that water melting later are getting less water overall, as it melts too soon and there is less of it to melt in the first place.

Looking at 147 rivers icings in the U.S. and Canadian Arctic using satellite data, Pavlesky and Zarnetske discovered that 84 of those are becoming smaller or disappearing earlier in the season. The minimum area of ice also shrank a lot during the study period. In 2000, there were 30 square miles of ice, but there were only 2 square miles in 2010. The minimum ice area has rebounded a little bit: it was up to 3 square miles in 2015.

“This is the first clear evidence that this important component of Arctic river systems—which we didn’t know was changing—is changing and it’s changing rapidly,” said lead author Tamlin Pavelsky of the University of North Carolina Chapel Hill.

The exact mechanisms of how climate change is affecting these rivers is as yet unknown, it could be that higher temperatures are directly affecting the ice, or that it is more subtly impacting groundwater, and how that water interacts with rivers.

“While glaciers tell us about climate in the mountains and sea ice tells us about sea-atmosphere interactions, the processes that control river icing may offer great insight into how groundwater and surface waters are connected in the Arctic and how our headwaters will be connected to the ocean in the future,” said study co-author Jay Zarnetske of Michigan State University.

In the meantime, these rivers and their related ecosystems are going to continue to change as the world’s overall climate warms.

Climate Change, Nature

Trees Have a Greater Impact on Climate than Previously Thought

Trees have a significant effect on the water cycle.
Trees have a significant effect on the water cycle, which aids in cooling the earth. Photo: Shutterstock

Trees are an important part of the conversation about global climate change, but according to a recent study, they haven’t been getting their dues. Much research has focused on trees as simple carbon sinks, and in general, it’s expected that they can’t offset the amount of carbon that is being out into the atmosphere. But many of those studies missed the forest for the trees, so to speak, and were looking at them from only a single viewpoint.

A recent study from the World Agroforestry Centre has compiled data from numerous other studies, from biologists, chemists, climate scientists, geologists, hydrologists, and even social scientists, and found that trees have a bigger impact that we thought. Trees have a significant impact on the water cycle, processing and redistributing water, which helps to cool the planet’s surface. Carbon sequestrations is essentially a byproduct of this.

Forests have an impact on food security and help to keep the world cooler despite rising temperatures. That will be especially important going forward, as the issue of climate change requires more than one approach. The Paris Agreement outlined both mitigation and adaptation in the future. The former means creating less pollution and increasing sequestration of carbon and other greenhouse gases where possible. The latter means finding ways to change agriculture, construction, and other human activities in ways that will work better with the changes happening to the Earth.

There is still much to be learned about how trees can help us to both mitigate and adapt to climate change, but this study is a good place to start.

“Some of the more refined details of how forests affect rainfall are still being discussed among scientists of different disciplines and backgrounds,” said Dr. David Ellison, lead author of the study. “But the direct relevance of trees and forests for protecting and intensifying the hydrologic cycle, associated cooling, and the sharing of atmospheric moisture with downwind locations is beyond reasonable doubt.”

Climate Change, Science

Snowpack Will Melt Earlier, More Slowly Due to Rising Temperatures

Snowpack will melt earlier, but more slowly, as a result of warming climate.
Snowpack will melt earlier, but more slowly, as a result of warming climate. Photo: Shutterstock

Rising global temperatures will most likely result in mountain snowpack melting earlier in the year, but at a slower rate. While that may seem confusing at first, the mechanism is pretty easy to explain. Typically, most snowpack doesn’t start melting until the summer, when the sun in strongest in that region, and then it melts quickly.

But “when snowmelt shifts earlier in the year, the snow is no longer melting under the high sun angles of late spring and early summer,” said study lead author Keith Musselman. “The Sun just isn’t providing enough energy at that time of year to drive high snowmelt rates.”

But rising temperatures will mean less snowfall generally, so there will be less snow—and that snow will be melting more slowly over a longer period. That means less danger of flashfloods in certain areas, but it can also have a number of negative impacts. For one, slower melting means less water ends up in streams because it gets soaked up by plants instead. This, in turn, means that the streams have less water, which can impact whole ecosystems, as well as urban water supplies that rely on seasonal snowmelt

“We found a decrease in the total volume of meltwater—which makes sense given that we expect there to be less snow overall in the future,” Musselman said. “But even with this decrease, we found an increase in the amount of water produced at low melt rates and, on the flip side, a decrease in the amount of water produced at high melt rates.”

The impacts could reach far beyond the immediate area affected. Reductions in melt rates could mean fewer spring floods—which would be great for infrastructure, but not so good for the ecosystems that depend on those annual floods. The meltwater will likely be warmer, which could affect trout and other fish species.

These are some significant and problematic implications, though how exactly we can deal with such problems remains to be seen. Obviously, this is another piece of evidence in favor of working to combat global climate change.