When are extreme events part of natural climate variability and when are they due to climate change? It’s important to ask—no matter where you stand on the role of humanity’s impact on the environment.

A group of international scientists decided to address this question, focusing on a dozen or so extreme events from 2012. Their results were published last week in the Bulletin of the American Meteorological Society. (The findings are also available in a downloadable report.)

And the results, were, well, variable.

The researchers did not look at Hurricane Sandy, but they did examine the flooding and the inundation it caused. Because of sea-level rise (a direct result of climate change), the researchers determined that the superstorm did far greater damage than it would have with oceans at normal levels.

The team also determined that heavy rains in the United Kingdom, Japan, and China were not due to global warming, and Australia’s above-average rainfall was due to a La Niña event (or short-term climate variability).

However, a deluge in New Zealand was due to climate change. From Wired:

Total moisture available for this extreme event was 1% to 5% higher as a result of anthropogenic greenhouse gas emissions.

And Arctic sea ice melt? The cap of sea ice covering the North Pole shrunk to its smallest extent last summer. The cause? Climate change.

What about last year’s devastating drought in the Midwest? Scientists judged that climate variability was to blame—not global warming.

However, Stanford researchers did find that the extreme heat that came with last summer’s drought could be attributed to climate change. They also found strong evidence that the high levels of greenhouse gases now in the atmosphere have increased the likelihood of severe heat.

In addition, their findings indicate that extreme weather in the north-central and northeastern United States is more than four times as likely to occur than it was in the pre-industrial era.

The Palo Alto scientists hope the results from these studies can help to quantify the true cost of emissions to society, since the cost of the disaster is measurable.

“Knowing how much our emissions have changed the likelihood of this kind of severe heat event can help us to minimize the impacts of the next heat wave, and to determine the value of avoiding further changes in climate,” says lead author Noah Diffenbaugh, a Stanford associate professor of environmental Earth system science.

Image: Theresa L Wysocki/Flickr

As scientists understand more about microbes, it seems that the miniscule life forms have the potential to contribute to a host of useful activities—making biofuels, fighting human disease, improving high tech, you name it!

Now, a feature article in the September issue of Scientific American looks at how soil microbes could revolutionize agriculture.

Soil microbes include everything from bacteria to fungi, and article author Richard Conniff likes to call the lot collectively “the agribiome.” These microscopic life forms have the potential to solve many crises facing agriculture today—everything from climate change and drought to Salmonella and other food-bourn illnesses, from the costs of man-made fertilizers to the GMO controversy.

Conniff’s article comes on the heels two other papers that highlight the importance of soil microbes. In a paper published last week in the Proceedings of the National Academy of Sciences, a team of British scientists emphasizes how important soil microbe diversity is for European crops. And two weeks ago, American researchers determined that soil microbes are responsible for controlling carbon in the soil—an important factor in retaining the important mineral in the dirt as temperatures rise and the climate warms.

The Scientific American article gives many examples of these crucial, unseen microbial workers. Bacteria found in soil on the United States West Coast can kill Salmonella, Conniff reports, so the USDA is looking at introducing the bacteria in East Coast soils to stop the occasionally deadly outbreaks.

And instead of genetically modifying actual crops to withstand drought conditions, Mexican scientists are looking at modifying bacteria to strengthen the plants in the soil at their roots.

Mycorrhizal fungi in the soil are heroes in both the SciAm article and the PNAS study. The fungi deliver much-needed phosphate to crops, an easier and cheaper way to get the important mineral to the plants to help them grow. Artificial fertilizers can be expensive, especially for farmers in developing countries, and harm the natural soil ecosystem. Run-off from these fertilizers also contaminates freshwater and marine environments. A simple animation of how the fungi works to help plants is available here.

(Mycorrhizal fungi also play a heroic role in the next Academy planetarium show! Currently in production and set for a fall 2014 opening date, the latest production from our visualization studio will highlight the complex relationships in ecosystems—and how humans fit into the picture.)

If farmers and scientists can acknowledge that collaborating with microbes can play a crucial role in farming, “we will have come a step closer to feeding a hungry world,” Conniff concludes.

The lead author of the PNAS paper, Franciska de Vries, says, “This research highlights the importance of soil organisms and demonstrates that there is a whole world beneath our feet, inhabited by small creatures that we can’t even see most of the time. By liberating nitrogen for plant growth and locking up carbon in the soil they play an important role in supporting life on Earth.”

Mycorrhizal fungi image: Nilsson et al. BMC Bioinformatics

Happy Earth Day! We would like to share a few recent headlines for you to peruse to ponder and protect our planet…

Pollution
From high to low, all around the world, pollution affects our world. Recent headlines show that “Toxic chemicals are accumulating in the ecosystems of the Himalayas and the Tibetan plateau,” according to Nature. Tiny plastic particles aren’t just trouble in the oceans; the Great Lakes contain millions of microplastics, too. The New York Times’ Dot Earth blog has a short post about the importance of not littering. And National Geographic has an article about how pollution on land can affect marine life like dolphins and local sea otters.

Colorado River
While many U.S. rivers have problems with pollution, the Colorado River’s mismanagement, overuse and drought put it atop the list of Endangered Rivers of 2013. National Geographic has an entire series on the Colorado River delta, and the New York Times has offered both an article and video last week on the region’s hopeful revival.

Drought
Speaking of drought… Do drought-stressed trees cry for help? French scientists are listening for clues. Climate change was not responsible for last summer’s Midwestern drought, according to NOAA, but then what was? And how might we be able to predict future droughts?

Climate Change
Climate change may not have caused of the recent drought, but it is responsible for other devastating events and looming disasters: bumpier flights, more storms, bark beetle plagues, drowned islands, failures in agriculture systems and more extinctions. Researchers are also getting a better handle on tracking climate change through mapping ocean eddies and looking at historic ocean temperatures and air pressure.

Ecology
How do species react to environmental changes? Rapid evolution, according to one study. Another study suggests that endangered species are already doomed. And Nature offers an update on a decades-long study of habitat fragmentation in the Amazon.

Energy
How has energy usage in our country changed over the past two hundred years? NPR has a graph (or four) for that. In response, Scientific American presents a diagram illustrating our potential for future alternative energy use and resources accompanying an article titled, “How to Power the World without Fossil Fuels.” Germany seems to have taken notice—the European country has ambitious renewable plans. But it’s not the only one. The U.S. had a huge year in 2012 for wind power. And, heading across the country soon? How about a solar-powered flight?

Earth Day
Finally, let’s truly celebrate the planet’s holiday with history, maps, jokes about Earth Day, and facts and photos of our beautiful home.

Image: Terra/ASTER/NASA and NASA Earth Observatory

Each fall, monarch butterflies east of the Rockies make the long migration to their overwintering site in Mexico. Scientists have exposed the internal rhythms that tell the butterflies where to go, despite the fact that the site was last visited by their great-grandparents. But how do the butterflies know when it’s time to leave Mexico and head north again?

Researchers at the University of Massachusetts suspected that temperature or daylight had something to do with it, so they collected wild monarchs at the start of their southward fall migration, brought them into the lab, and divided them into three groups. Two of the groups were exposed to the same cooler temperatures they would experience in their overwintering ground in Mexico. In addition, one of these two was also exposed to the same changing light levels they would experience south of the border. For the third group, the temperature remained warm and light levels never changed.

When placed into a flight simulator 24 days later, the first two groups of monarchs began flying northward. The third group, not exposed to cooler temperatures, continued flying southward.

If temperature alone determines when the butterflies start their northward migration, scientists raise concerns about the effects climate change will have on these beauties. “Without this thermal stimulus, the annual migration cycle would be broken, and we could lose one of the most intriguing biological phenomena in the world,” says Steven Reppert. His study, coauthored with Patrick Guerra, appeared last month in Current Biology.

Sadly, on the heels of that study comes a report issued last week on the decline of monarch numbers in Mexico this past winter. The study blames drought in the American southwest and an increase in soy and corn farming. Both are responsible for a loss in the milkweed plants the butterflies rely on for food during their long migrations.

“If people want to help,” says Craig Wilson of Texas A&M University, “they can pick up some milkweed plants right now at local farmer’s cooperative stores and this would no doubt be a big boost to help in their migration journey. It is important to have a national priority of planting milkweed to assure there will be monarchs in the future. If we could get several states to collaborate, we might be able to provide a ‘feeding’ corridor right up to Canada for the monarchs.”

Image: Kenneth Dwain Harrelson/Wikipedia

Four amazing and passionate scientists discussed different aspects of our changing world—wildlife, drought, storms and the tree-ring record—at a press conference titled, “Did Climate Change Cause Superstorm Sandy?”

Remember, these are scientists, not politicians (see more in Andy Revkin’s New York Times blog). They need evidence to see causal effect between one event and another. And for these recent storms and weather patterns, there just isn’t enough evidence. Yet.

But are these researchers glad that these events are focusing Americans’ attention (including the President in his recent State of the Union address) on climate change? Most definitely. Yes.

Here’s what they do know. Climate change is affecting the probability of storms like Sandy and Nemo. There is evidence that in our warming world, severe storms will happen more frequently.

Researchers understand that global warming and other human-related activities are affecting where animals live, move and mate, and when plants bloom.

Scientists also know that temperature increase is one factor in drought. Texas temperatures have risen steeply in just the past 15 years and drought has increased.  And now Texans are talking about climate change, said John Nielsen-Gammon of Texas A&M University. The drought alone didn’t alarm them about climate change, but the decreased water supply has made people and politicians alike take notice.

And the speakers are hopeful and passionate that we’ll start doing something about these effects—reducing fuel emissions, restoring habitats, becoming more aware of climate change.

What do you know and feel? Share with us here.

Midwest drought image: cwwycoff1/Wikipedia

Since the mid-1960s, the Palmer Drought Severity Index (PDSI) has been the standard of measuring drought, reviewing temperature and rainfall information over a period of time. But a recent study in Nature states that the measurement may be too simple.

The PDSI looks at potential moisture evaporation from the soil in terms of temperature and plant use. But researchers at Princeton University see other clues to evaporation—wind speed, humidity and solar radiation—that could contribute to the evaporation and drought estimation.

The Intergovernmental Panel on Climate Change (IPCC) uses the PDSI to assess drought. In their 2007 report, they noted that droughts have intensified since the 1970s. But the Princeton team finds that there has been little change in droughts over the past 60 years. According to Science Now,

… the new assessment technique found that between 1980 and 2008, the global area stricken by drought grew by approximately 0.08% per year—less than one-seventh the increase estimated by the temperature-only version of PDSI…

The results of the study have implications for how we interpret the role of global warming on changes to the weather and its extremes like drought. The authors stress that this finding does not rule out drought as a response to future climate change. It just gives scientists a better way to measure and predict drought.

Tomorrow: Sustainable groundwater

This week, we’ll look at recent research on water and climate. Today we’ll start in the past, to understand how climate and water affected human life hundreds of years ago.

The collapse of the Maya is one of the world’s most enduring mysteries. But a recent study in the journal Science, combining a precise climatic record of the Maya environment with a precise record of Maya political history, may provide a better understanding of the role weather had in the civilization’s rise and fall.

And it all has to do with water—plentiful rainfall, followed by drought. The researchers studied the isotopes in 2,000 year-old stalagmite samples from a cave in Belize. Nature News describes the process:

The team estimated historical rainfall in the Mayan lowlands by measuring oxygen isotopes incorporated into the stalagmite from rainwater that seeped into the cave from the ground above. The precipitation levels were tied to specific dates by measuring the ratio of radioactive isotopes in the stalagmite.

“Unusually high amounts of rainfall favored an increase in food production and an explosion in the population between AD 450 and 660,” says Douglas Kennett, lead author and professor of anthropology at Penn State. This high amount of rainfall, he says, was followed “by a series of major droughts that triggered a decline in agricultural productivity and contributed to societal fragmentation and political collapse. The most severe drought (AD 1020 and 1100) in the record occurs after the widespread collapse of Maya state centers and may be associated with widespread population decline in the region.”

Social unrest is often tied to drought and food availability. If drought should persist because of global warming in the future, perhaps we can learn from the Maya, says co-author Bruce Winterhalder, of UC Davis. “It’s a cautionary tale about how fragile our political structure might be. Are we in danger the same way the Classic Maya were in danger? I don’t know.”

Tomorrow: Are droughts overestimated?

Image: Douglas Kennett, Penn State

The Morrison Planetarium’s monthly Earth Update, a monthly “Science Tonight, Live@630” presentation at NightLife, takes visitors on an immersive trip around the world examining current events on our blue planet—including climate, weather, seismic activity and more. The tour is created and navigated by Tim Horn, our producer of climate and earth science visualization and presented by our expert planetarium presenter, Josh Roberts.

We like to follow up with an article here, with a summary of the latest earthly news that we discussed in the dome.

This month, Josh and Tim started at the Sun.  On the last day of August, a coronal mass, a long filament of charged particles trapped in the Sun’s magnetosphere, was ejected into space at a speed of over 900 miles per second!  Luckily it didn’t travel directly toward Earth. Similar coronal mass ejections can head toward us, however, which makes them well worth studying.

Leaving the Sun, Josh and Tim returned to our planet, with images courtesy of the NASA Earth Observatory.  This year, the National Climatic Data Center reported the hottest July on record in the contiguous United States.

Check out this natural-color image of Hurricane Isaac over Louisiana on August 29 from NASA’s Terra satellite.  Within several hours of this photo, the hurricane was downgraded to a tropical storm.  Issac claimed five lives, but the storm also brought beneficial rains to parts of the drought-stricken Midwest.

Speaking of drought… In July, the US Drought Monitor announced that over 53% of the country suffered in moderate drought or worse.

The remnants of Isaac eased the dryness dramatically in Arkansas, Missouri, Illinois, and Louisiana, while rains also moistened states in the mid-Atlantic and Southeast.

But to the west, 100-degree-plus temperatures and a continued lack of precipitation pushed Oklahoma, Texas, Nebraska, Kansas and the Dakotas deeper into drought. Wyoming and Montana also got drier.

Looking at the western United States, we viewed another natural-color image showing several wildfires.  That image, from the Aqua satellite, was taken on August 12.

But it’s not all doom and gloom.  The recent earthquake in Costa Rica caused “remarkably little” damage. If you’ve visited the Academy’s new Earthquake exhibit and seen our planetarium show, you know that preparedness plays a key role in people’s and communities’ abilities to cope with an earthquake. And societies prepare for earthquakes by building resilient infrastructure.  Strict building codes, similar to those of California and Japan, helped Costa Rica stay intact, despite the 7.6 magnitude quake. The Boy Scouts were right,  “Be Prepared.”

Join us next month for more Earth Update!

Kathi Koontz is production coordinator for the Worldviews Network here at the Academy. She works with planetariums across the country to display immersive science visualizations on local environmental topics.  They partner with local non-profits and NGOs to share what they are doing and inspire action.

Oops!

Last winter we attended the AAAS Meeting in Vancouver, BC and listened to the University of Texas’ Charles Groat downplay the effects of fracking. We posted a bit of that news in an article about increased fracking regulations in April.

This week, Science Insider reports that Groat neglected to mention that he serves on the board of (and receives quite a bit of funding from) an oil and gas company that conducts fracking. Sounds like a bit of a conflict of interest, doesn’t it?

Really Old Polar Bears

In April we also ran a story about polar bear evolution. Researchers, studying nuclear DNA, put polar bears’ origin to 600,000 years ago.

But a new study, published earlier this week in the Proceedings of the National Academy of Sciences, suggests that polar bears evolved into a distinct species as many as 4-5 million years ago and did not recently descend from brown bears, despite shared genetic material.

The authors conclude that brown bears and polar bears interbred intermittently over the years. The New York Times compares this to humans in a funny, relatable way:

The progress of species formation, at least in this case, is a bit like a long, ambivalent divorce in which the two parties separate but occasionally fall back into bed even after the official decree.

Drought

Last week, we wrote about the devastating drought engulfing our country. This week Brandon Keim, writing in Wired, describes how this tragedy could reach beyond our borders and create global unrest.

Reporting on a recent study by the New England Complex Systems Institute, Keim says that commodity speculation (that food prices will rise due to the drought) may drive conflict in developing countries. The study reports that recent history demonstrates this trend:

During the last six years, high and fluctuating food prices have lead to widespread hunger and social unrest.

An article in Nature also explores this global impact.

Rain, rain…

Finally, earlier this summer, before drought was a harsh reality, we described mosquitoes amazing ability to fly through the rain. Now, a new study in Proceedings of the Royal Society B, demonstrates that hummingbirds are equally as adept in heavy downpours.

According to the abstract, UC Berkeley’s Victor Manuel Ortega-Jimenez and Robert Dudley found that:

…birds hovering in heavy rain adopted more horizontal body and tail positions, and also increased wingbeat frequency substantially, while reducing stroke amplitude when compared with control conditions.

These dynamics can be applied to robots, say the authors. No surprise, given both scientists are part of Berkeley’s Integrative Biology department—where many bio-inspired robotic ideas come from.

Image: User:Mdf/Wikipedia