7 Visions of Our Hot, Awful Future

It wasn't so long ago that some hope lingered around global warming--a dedicated international effort could still turn things around and prevent catastrophic change. But have we now crossed the threshold? Last year in A World Without Ice, Henry Pollack put it simply: "Change is underway and is certain to continue, because of inertia in both the climate system and the global industrial economy; it is impossible to simply pull the plug and stop these systems in their tracks." Global warming is going to happen, and perhaps disastrously so.

And the zeitgeist has turned towards resignation, if 2010's books--with their gloomy covers featuring melting ice and submerged skyscrapers--are any indication. We've assembled their predictions, so you know what to expect from our hot future.

Pacific islands left thirsty by La Niña

The Pacific island nations of Tuvalu and Tokelau have declared a state of emergency due to severe water shortages. In response, New Zealand has sent water and two desalination units, and Samoa has also sent water.

Both nations rely on rain for drinking water, but there has been little rainfall for the past four months, says Richard Gorkrun of the Tuvalu Meteorological Service in Funafuti, Tuvalu. "Some villages in Tokelau only have enough water until the end of this week," says Jo Suveinakama of the Tokelau government.

A weak La Niña is causing the drought by cooling the surface of the sea around Tuvalu, says Daniel Corbett of forecasters MetService in Wellington, New Zealand. The cool waters have forced a large band of cloud off course.

"Normally the band would be flirting with Tuvalu and producing afternoon showers over the islands," says Corbett. "But now it's too far south, so they have been bone dry."

The clouds are not expected to return until next year.

Groundwater greed driving sea level rises

SLOWLY and almost imperceptibly the seas are rising, swollen by melting ice and the expansion of seawater as it warms. But there's another source of water adding to the rise: humanity's habit of pumping water from underground aquifers to the surface. Most of this water ends up in the sea.

Not many scientists even consider the effects of groundwater on sea level, says Leonard Konikow of the United States Geological Survey in Reston, Virginia. Estimates were published as far back as 1994 (Nature, DOI: 10.1038/367054a0), but without good evidence to back them up, he says. The last report of the Intergovernmental Panel on Climate Change said that changes to groundwater reserves "cannot be estimated with much confidence".

Konikow measured how much water had ended up in the oceans by looking at changes in groundwater levels in 46 well-studied aquifers, which he then extrapolated to the rest of the world. He estimates that about 4500 cubic kilometres of water was extracted from aquifers between 1900 and 2008.

That amounts to 1.26 centimetres of the overall rise in sea levels of 17 cm in the same period (Geophysical Research Letters, DOI: 10.1029/2011gl048604).

That 1.26 cm may not seem like much, but groundwater depletion has accelerated massively since 1950, particularly in the past decade. Over 1300 cubic kilometres of the groundwater was extracted between 2000 and 2008, producing 0.36 cm of the total 2.79-cm rise in that time. "I was surprised that the depletion has accelerated so much," Konikow says.

It's not clear if the acceleration will continue. Konikow points out that some developed countries are cutting back on aquifer use and even trying to refill them when there is plenty of rainfall. "I would like to see that implemented more," he says.

"While there remain significant uncertainties, Konikow's estimate is probably the best there is for groundwater depletion," says John Church of CSIRO Marine and Atmospheric Research in Hobart, Tasmania, Australia.

Ice-age nettles may survive in dark Chinese caves

Walk into a cave in south-west China and you could be stepping back 30,000 years in time.

So says Alex Monro, a researcher in tropical plant diversity at the Natural History Museum, London, who thinks the caves could be a time capsule preserving rare nettles from the time of the last ice age.

Working with researchers from the Chinese Academy of Sciences, Monro has identified seven species of nettle that grow in isolated, dark corners of the karst landscapes of Guangxi and Yunnan provinces. Some species can survive in conditions in which just 0.02 per cent of sunlight penetrates the cave – that's less than reaches 100 metres deep into the oceans. "They grow at the backs of the main caverns in near-dark conditions," says Monro.

"Some of the specimens came from areas with very low light levels indeed, and one can easily interpret the site as being under full cave conditions," says Frank Howarth of the Hawaii Biological Survey in Honolulu, a speleologist who specialises in karst caves and their ecologies.

"There must be something quite special about their photosynthesis," says Monro, although the team has not yet investigated the photosynthetic mechanism. "They probably activate the photosynthetic process very quickly, which enables them to take advantage of very short bursts of light, and they might go for slightly different wavelengths," he says.

The nettle species seem to be unique to the remote caves and gorges, growing in isolated groups. One species, Elatostema retrorstrigulosum, is limited to only 10 adult plants, some growing in a grotto, hidden among stalagmites. The team have identified two of the species as "critically endangered" under the criteria of the International Union for Conservation of Nature; the rest are either "endangered" or "vulnerable".
Cold blast from the past

Nettles like these are not found in the surrounding tropical forest. To explain the discovery of these pockets of rare plants in an environment that is too tropical to support them, Monro suggests that the rare species could be "relicts of a vegetation from a previous cooler climate that resembled that of the caves".

Ancient cave paintings threatened by tourist plans

Prehistoric paintings in northern Spain could be irreparably damaged if plans to reopen the Altamira cave to tourists go ahead. Local officials want to reopen the cave to boost the local economy, but visitors could heat the caves and introduce microbes that destroy pigments.

The Altamira cave paintings were discovered in 1879 and are thought to be at least 14,000 years old. The paintings have attracted huge numbers of visitors – 175,000 in 1973, the busiest year on record. But the cave was closed to the public in 2002 after photosynthetic bacteria and fungi were found to be consuming pigments at alarming rates.

Plans to reopen the caves could restart the damaging processes. A team from the Spanish National Research Council in Madrid have modelled the effect of visitors over a number of years and say that tourists would increase the temperature, humidity and carbon-dioxide levels in the cave, creating conditions in which microbes would thrive.

In addition, visitors would bring with them organic matter in the form of skin flakes, clothing fibres and dust, which microbes can consume. Air turbulence created by moving people would spread bacterial and fungal spores to other, previously unaffected spaces.
Another Lascaux?

Although reopening the caves might boost the economy in the short term, says lead researcher Cesáreo Sáiz Jiménez, the damage would outweigh the benefit. "The paintings are a legacy from the past and their importance exceeds local culture."

The researchers say they want to prevent the scale of damage that occurred at the Lascaux cave in France, where mismanagement led to successive waves of pathogens attacking wall paintings there. For example, pesticides intended to destroy microorganisms became a source of nutrients for them instead.

Sáiz Jiménez and his colleagues conclude that only isolation from the outside world can prevent the same kind of damage at Altamira.

Why size matters in the plant world too

Over 60 years ago, evolutionary biologist Bernhard Rensch calculated that males are typically the larger sex in big-bodied species such as humans, whereas females outdo them in small-bodied species such as spiders. Now it turns out that many plants obey Rensch's rule too.

Most plants produce both male and female sex organs, but around 7 per cent are dioecious, meaning individuals are purely male or female. Kevin Burns and Patrick Kavanagh at Victoria University of Wellington in New Zealand measured the leaf and stem sizes of 297 plants from 38 dioecious plant species in herbarium collections of the National Museum of New Zealand and discovered that they follow the sex-size rule

Hot Zone—A Warming Planet's Rising Tide of Disaster

It was a hot, sticky day when patient zero arrived at a local hospital in Brownsville, Texas, in June 2005. Her body was racked with chills, she couldn’t stop vomiting, her blood pressure was perilously low, and she was passing blood in her urine. Clueless as to the cause, doctors pumped her up with fluids to treat dehydration, dosed her with antibiotics, and sent her home. But when blood tests and clinical evaluation were done with the help of the regional Texas Border Infectious Disease Surveillance project, a surprising culprit was unmasked: dengue hemorrhagic fever, a deadly viral disease usually regarded as a risk only in the tropics.

Long thought eradicated in the United States, dengue is roaring back. There had been prior cases of the disease’s milder cousin, classic dengue fever, in Brownsville, a bustling metropolis of about 140,000 people at the southernmost tip of Texas on the Gulf coast. But this was the first well-documented case of the more serious form of dengue infection, hemorrhagic fever, in a Texas resident infected in the continental United States. It is unlikely to be the last. From 1995 to 2005, some 10,000 cases were reported in the United States and the Texas-Mexico border region. The Centers for Disease Control and Prevention (CDC) believes that many cases are never counted, so these figures may be a vast underestimate.

A range of factors influence the spread of the dengue virus, but rising global temperatures may be the most important of all. Like many tropical diseases, dengue is spread by mosquito bites, and mosquitoes are exquisitely sensitive to climate. Frost kills both adults and larvae, which is why the disease hadn’t previously been able to get a foothold in the United States. With the advent of warmer winters, there is nothing holding the insects back. As a result, the two species of mosquito capable of transmitting dengue fever—Aedes aegypti and Aedes albopictus, also called the Asian tiger mosquito—have substantially expanded their habitat range since the middle of the 20th century

The Future History of the Arctic

Viewed through certain eyes, the diminishing ice cover at the top of the world is not a harbinger of destruction but an open door to commerce. The Northwest Passage is coming, at last. The Arctic is loaded with resources, and today as the ice recedes and open water stretches further, energy developers are licking their lips at the chance to get at all that hydrocarbon booty buried beneath frigid seas. The fight to come is: Who has the rights to what?

Writes Charles Emmerson: "If there is a scramble for the Arctic, it is a scramble in slow motion." That's because going after Arctic energy resources requires not just waiting for the waters to become passable, but also negotiating the fact that "different legal regimes apply to the land, the sea, and the seabed." It might be easiest to negotiate a new treaty to govern the newly open Arctic, but Emmerson doubts this will happen. If for no other reason, he writes, the pool of Arctic nations would be inviting other nations to join the deliberations if they did so. It looks like the future of the Arctic will be legal mess, but it will be a legal mess sorted out by Canada, the United States, Russia, Norway, and Denmark (owner of Greenland) while the rest of the world watches from the sidelines.

The Weather of the Future

Can the Big Apple, a city of islands (and DISCOVER's home), be spared from rising seas and fiercer storms? As we covered earlier this year, there's plenty to do to save New York from encroaching waters. Some architects see a circle of marshland around Manhattan to keep the waves at bay, bringing back mollusks to create natural reefs, or raising buildings off the ground to keep them from flooding. But none of this will be cheap. In Peter Ward's thought experiment that saw Miami's doom, "the fight for New York alone had necessitated cuts to national defense to the point that that United States had completely withdrawn from its foreign bases, defaulted on its Social Security obligations, and abandoned its short-lived national health care system."

In her book, Heidi Cullen explains that there are more mundane annoyances on the way. She quotes Columbia University energy expert Steve Hammer: "For New York, climate change means blackouts." Plain and simple, more extreme heat means more AC running non-stop, and the city's power system won't be able to keep up. The water supply will be stressed as less precipitation will fall as snow on the Catskills, meaning less meltwater to flow to the city's taps.

Climatopolis

We are an adaptive species. Unlike the birds and butterflies, Matthew Kahn writes, we humans can adapt to whatever new world comes our way. An optimist in a pessimistic group, he focuses the upside of a disaster. For one thing, the Rust Belt could receive an overdue makeover. Given the steady declines of Cleveland, Buffalo, and Detroit, it sounds like a joke today to imagine them vibrant again. However, Kahn points to the revitalizations of Boston and New York City after the dreadful 1970s. If global warming makes the Sun Belt too sunny and unlivable, perhaps what was old will become new again. Foresight, he says, will be the key. People who buy Detroit property today for next-to-nothing will look good if the city booms again. "Climate change will create big profit opportunities for insurance companies that are nimble enough to accurately price the real-time risk that policy owners (such as homeowners) face in different locations," he writes.

His oddly specific prediction: We're all going to eat dried fruit in the future. Kahn reasons that growers will want to hold inventory to deal with market fluctuations brought on by climate-related agricultural disasters, and dried fruit keeps.