Credit: Ralph Clevenger/Corbis
EXPERIENCING is believing. It's one thing to marvel at a documentary about the Great Barrier Reef, and quite another to immerse yourself in the silent beauty and colourful diversity of the world's largest reef system.
Nothing less than being there really cuts it. The same applies to all the wonders of our blue planet. We've seen them in brochures, magazines, books and television travel specials - places we've always dreamed we might one day visit and experience up close.
One day. Eventually. There's all the time in the world. But when you look at the reality, maybe there isn't. In a world gripped by accelerating climate change, nothing is certain. If you take on board the predictions being made by the world's foremost climate researchers, you would be well advised to start planning those trips right now.
Global warming will be consigning much of the world we know and have taken for granted to the history books. Sure, you'll be able to read about these wonders of the world, but no one will ever again be able to experience them firsthand. The next few decades really are your final window of opportunity.
1. Mt. Kilimanjaro, Tanzania
WIDE AS ALL THE WORLD, great, high and unbelievably white in the sun," wrote Ernest Hemingway in the book The Snows of Kilimanjaro about the ice fields atop Africa's tallest mountain. Though he didn't intend it, his majestic words have become a major selling pitch used by countless tour operators hawking a once-in-a-lifetime experience - the chance to hike to the top of the 5,896-metre peak and witness one of the world's last tropical glaciers.
Every year, some 10,000 vacationers take up the challenge, and the climb has become a major part of Tanzania's international tourist trade. Snowcapped and shrouded by clouds, the local Chagga people called the mountain Kilema Kyaro, meaning 'that which cannot be conquered'. Sounds kind of 'eternal', doesn't it? However, Kilimanjaro's white top is fast disappearing and if you want to experience the spectacle then you'd better not leave it too long.
By 2000, about 82% of the ice fields first mapped in 1912 had been lost. In 2002, it was predicted that they would vanish altogether sometime between 2015 and 2020. And now scientists believe that the melting may be speeding up as there has been no accumulation of new ice forming since 2000. Which all adds up to the likelihood that the snows of Kilimanjaro will disappear within a few years.
When they melt it's feared that much of the country's tourism will also dissipate - causing a significant slump in Tanzania's economy.
But, if you're worried about the loss of a tourist destination, spare a thought for the people and the ecosystems around the mountain who will lose a significant part of their water supply.
The population living around the base of the mountain depends on melt water flowing from the glaciers. The inevitable loss of the ice fields is likely to add to the heavy drought burden already facing them.
The decline of tropical glaciers, as any climatologist will tell you, is a good global indicator of a warming world, and it's a trend being seen everywhere. But surely there will always be some glaciers to visit if you venture to the world's colder climes?
2. Glacier National Park, USA
IT'S INCREASINGLY HARD to understand why it's called Glacier National Park, because the glaciers are getting hard to find." So remarked Bruce Babbitt, secretary of the interior under former U.S. President Bill Clinton and one-time presidential candidate. That was in 1998.
Since then, several more glaciers have dropped off the map. In north western Montana, bordering Canada, lies one of the world's iconic natural wonders: Glacier National Park. Considered by many to contain some of the globe's most beautiful mountains, the area is called 'the backbone of the world' by the local Blackfoot Native Americans.
The glacier-carved mountains are steep, snowcapped and punctuated by stunning lakes, creeks - and a shrinking number of glaciers. In 1850, the area contained some 150 majestic glaciers.
Today that number stands at just 27, and the largest glaciers are only about a third of their original size. The area of the park covered by glaciers has declined by over 73%.
Computer modelling suggests that, if global warming continues at the current rate, then all the glaciers in the area will disappear by 2030. It's all part of a worldwide pattern that has been accelerating since 1980.
But the loss of the park's glaciers goes much further than the loss of a tourist icon. It may well also have a devastating impact on natural ecosystems that have taken thousands of years to develop in their shadows. The natural treasures that the national park was created to protect may go down the gurgler along with the ice.
3. Hudson Bay, Canada
"EVERY OCTOBER AND NOVEMBER along the west shore of Hudson Bay, scores of polar bears gather and wait for the waters to freeze. Their vigil anticipates the annual hunt for their choice prey, seals. The polar bear is normally a solitary creature, so this is one of nature's extraordinary events that gives you an opportunity to observe this remarkable creature up-close and in safety."
Sounds pretty special, doesn't it? This is the sales pitch of one travel company that prides itself on its responsible approach to tourism. You can choose from 60 options as to how you'll encounter these majestic animals, from a one-night excursion to more than a week out on the tundra with expert polar-bear watchers giving you the ultimate experience, which is a bargain at a total cost of between A$3,000 and A$10,000 (US$2,270 - $7,500).
To make you feel even better, part of the profits go toward the conservation of polar bears. But if you want to witness the splendour of the world's largest land carnivore and the apex predator of the Arctic in the wild, you may not want to delay too long: in spite of the best care taken by the tour operators, it's unlikely there'll be many bears around in 20 to 30 years.
Unless the amount of greenhouse gases that warm the atmosphere falls dramatically over the next few years - an unlikely occurrence - it's expected that there will be no summer ice in the Arctic at all by 2050.
In August 2006, satellite images showed that so much Arctic ice cover had disappeared over that month that a ship could have sailed unhindered from Europe's most northerly outpost of Spitzbergen, a Norwegian island, to the North Pole itself.
Well before the last ice melts, the bears will have lost their den sites, feeding grounds and migration corridors. So fast are the changes happening in the Arctic that there are likely to be few or no polar bears in the wild by around 2030.
The decline in bear numbers is already well documented. In the past few decades, populations have plummeted in many regions, and there's disturbing new evidence of polar bears drowning after being forced to swim up to 95 km over open sea in search of food.
Reports have emerged that, in some areas, bears are practising cannibalism as competition for food supplies heats up. If all this talk of disappearing ice and drowning bears is too depressing, then maybe you should escape to an isolated tropical island - surely a place beyond the cares of climate change?
4. Tuvalu and other Pacific paradises
IT'S ONE OF THE WORLD'S smallest nations and among the most remote. Tuvalu is mostly shorefront, rich with coconut trees and empty white-sand beaches. The coral reefs are intact and make for exciting diving, and the people are welcoming.
To reach this tropical paradise you'll need to fly about 1,000 km north from the Pacific island nation of Fiji. However, if you want to get there in time to take in the sights, you should pack your bags and catch one of the next flights out: rising sea levels are posing such a threat that native Tuvaluans are already leaving.
Tuvalu is spread over 800 km of ocean with an elevation of no more than 5 m above sea level. It consists of nine tiny islands, five of which are coral atolls, and the total area of land is a mere 26 km2.
Just under 12,000 people live there. The government of Tuvalu is so concerned about climate change and the threat of rising sea levels that it has already purchased land in Fiji and re settled some of its population.
It's currently looking for more land. And it's not just rising sea levels that threaten to remove this scattering of dots from the map.
The changing climate is also bringing fiercer, more frequent storms that are already eroding burial grounds and washing out crops. Within the lifetime of some of today's residents, these surges will likely transform this island idyll into an uninhabitable collection of rocks.
By way of example, in 1997 a cyclone slammed into one of the country's smaller islets and blew all its vegetation out to sea. Stripped of its coconut and pandanus trees, soil and sand, today the island is nothing more than a navigational hazard. This could well be the fate of the whole island group of Tuvalu.
And if storm surges and water levels weren't enough to dampen their spirits, the locals have recently been noticing another climate related threat: coral bleaching is on the increase as the ocean waters warm. Their precious coral - the main tourist drawcard of the area - is withering as the temperature rises.
Other low-lying nations in the same neighbourhood - including Kiribati, Niue, and the Marshall Islands - are in similar dire straits.
5. Great Barrier Reef, Australia
IT'S NO EXAGGERATION to say that it's one of our planet's greatest natural assets.
Stretching 2,300 km along Australia's east coast, the Great Barrier Reef consists of around 3,000 separate coral reefs built from more than 360 species of hard coral, hosts more than one third of Earth's soft coral species and is the world's largest breeding area for the green turtle.
Sad to say, then, that most reef experts believe that these corals don't have a place in a warming world.
Which seems particularly unfair because, as ecosystems go, coral reefs are reasonably resilient things. You can hit them with Force 5 cyclones and they'll usually bounce back fairly quickly.
If the sea level rises slowly, it's likely they'll be able to grow sufficiently to maintain themselves at just the right depth. But raise the water temperature by only one to two degrees for any length of time, and they're doomed.
Scientists don't know exactly why, but when the temperature goes up, the colourful plant part of the coral — known as zooxanthellae — jumps ship, leaving the coral looking bleached.
Without the photosynthetic zooxanthellae to provide food, the coral usually dies soon after. And while coral reefs can recover from bleaching, they are unlikely to do so if bleaching conditions continue year after year.
Yet that is exactly what experts fear is in store for the world's largest continuous coral reef. By 2030, scientists predict, severe bleaching events will be on the cards every year.
Further danger comes in the form of the rising levels of carbon dioxide in the atmosphere causing the oceans to become more acidic; this reduces the coral's ability to secrete new skeletons and grow. Many scientists believe that increasing acid levels in the oceans pose a threat to corals equal to that of rising water temperatures.
Either way, don't put off that big trip to the reef you've been daydreaming about.
6. Bwindi National Park, Uganda
THERE ARE FEWER THAN 700 of them left and you won't find any of them in a zoo. First discovered in 1902, the mountain gorilla is on the verge of extinction. The last survivors can be found in the Bwindi National Park in south-west Uganda, and in the mists of the Virunga Mountains of north-east Central Africa.
Mountain gorillas have gigantic features and are the darkest and hairiest of their kin. The average mature male weighs 160 kg and towers up to two metres when upright. Their large, burly arms are longer than their legs and they have enormous chests and massive crested heads.
While generally shy and calm, a dominant male silverback can put on an awesome performance when threatened. According to those who have had the opportunity, getting close to a family group of these gentle giants is an unbelievably moving experience.
In Uganda, groups of no more than six people are allowed to track a gorilla group, provided that they stay at least seven metres away from the animals at all times. Your chances of sighting gorillas are good, but not guaranteed. To be successful, you need some luck and a skilled tracker. All gorilla trackers need a permit and the waiting list is long, so book well in advance.
While the mountain gorillas are well-monitored and protected, and the ecotourism brings in valuable money that supports their ongoing conservation, the sad and inescapable truth is that their habitat is restricted and shrinking year by year.
The mountain gorilla lives in the highland forests between altitudes of 2,500 and 4,000 m. They're trapped in their mountain refuges, and as the climate warms, the trend everywhere is for these high altitude ecosystems to retreat higher as conditions lower down become too hot or too dry.
Over the course of the 20th century, mountain-dwelling species have retreated, on average, just over six metres up the slope of their homes each decade. It's anticipated that this uphill migration will only accelerate in the coming decades.
No one has estimated when the death knell for the mountain gorillas might sound, but with only 700 left and the mercury rising, not to mention their location, in countries devastated by famine, war and drought, you don't want to leave this experience too long.
7. Venice, Italy
FOR MUCH OF ITS HISTORY, Venice has benefited from its proximity to the sea. Surrounded by waters too deep for enemy armies and too shallow for hostile navies, Venetians live not so much by the sea as in the sea. But now, rising water levels are placing a big question mark over the
future of the historic port.
Paintings by the Venetian master Canaletto show that the waterline was 80 cm lower two centuries ago. St Mark's Square was flooded seven times in 1900 - but 99 times in 1996. And that could be just the beginning. Venetians are familiar with high tides invading their city and piles of sandbags and elevated wooden walkways are routinely used to help the population navigate around the worst of the flooding.
But this kind of band aid solution is powerless against the rising menace of global warming. The Intergovernmental Panel on Climate Change — a group of the world's leading climate scientists established by the United Nations — warns that the world's oceans could rise by up to 90 cm this century. Couple that with an increased intensity in storms and things are looking decidedly damp for the people of Venice.
After nearly four decades of debate, the construction of an ambitious large scale barrier between the Venetian lagoon and the Adriatic Sea has finally begun.
Project Mose (short for Modulo Sperimentale Elettromeccanico, or experimental electromechanical module, but also an allusion to biblical miracle-worker Moses and his ability to part the sea) will cost a staggering €3 billion (A$5 billion).
It consists of 79 hinged steel gates, each 30 m high, 20 m wide and 4 to 5 m thick. At the three inlets where the Venetian lagoon meets the Adriatic, these hollow gates will, for the most part, be filled with water and lie unseen on the ocean floor. In the event of a storm or high tide warning, they will be pumped full of air and rise up to form a wall against the tide.
While most agree it's an elegant solution to a problem of epic proportions, the gates will be obsolete within 50 years if predictions about sea level rises are realised. A sea level increase of 20 to 30 cm is all that's required to render them useless.
Fourteen million tourists pour into Venice each year. With its Old World charm, famous canals, gondolas and cathedrals, the city is like a piece of living history. But for the generations to come, the City of Canals may live on only in memory.
8. New York City, USA
A COUPLE OF YEARS AGO, no one would have believed that New Orleans - the birthplace of jazz and one of the world's unique cities - was about to be smudged from the tourist destination map. But that's exactly what Hurricane Katrina did when it struck in August 2005. Surely the same thing couldn't happen to New York?
In a warmer world with a greater number of killer storms, this cannot be ruled out. Records show that the yearly number of hurricanes that reach Category 4 or 5 has doubled since 1970, and there are many precedents for hurricanes reaching New York: in 2004, the remnants of Hurricane Frances flooded New York's subways, and the city that never sleeps has scored direct hits from smaller hurricanes in the past.
And, if you remember the terror that followed in Katrina's wake in New Orleans; the inability to rescue tens of thousands of stranded people, and this in a minor city of around 200,000; imagine the havoc that would be created if a hurricane struck a behemoth with a population of more than 10 million.
For all the noise it makes, it needs to be remembered that New York City is just three little islands and a bit of mainland laced together by 80 bridges and tunnels.
And the entries to many of these tunnels are barely above sea level, if at all. Even if storms are no more frequent or intense than they are today, flooding could increase simply because the sea level will be higher.
During a full moon in December 1992, a strong north-east wind lifted the water levels a couple of metres above their normal peak and flooded the southernmost tip of Manhattan. The floodwaters surged onto highways and streets, paralysing the entire city and disrupting the lives of the 21 million people in the greater New York area. And that was only a strong wind at high tide.
As sea levels continue to creep ever higher, there is a growing threat of more damaging storm surges, as well as an anticipated increase in the frequency of damaging flood events that previously occurred only once every 100 years. Indeed, by 2080, it's projected that these once-a-century disasters will be occurring, on average, every four years.
According to estimates from the U.S. Army Corps of Engineers, beach erosion rates due to increasing sea levels will double or even triple in the New York region by the 2020s. New Orleans may never return to its former glory, but you still have a chance to take your bite out of the Big Apple if you hurry.
9. The snowfields, Australia
THERE'S NOTHING QUITE LIKE that rush you get as you weave down the ski slope carving neat lines in deep white powder. But skiers have been lamenting the fact that, in recent years, the white stuff hasn't been all that deep, or powdery.
Records reveal that there's been a slow decline in snow depths since 1957. The Australian Bureau of Meteorology has found that, in one area in the Snowy Mountains, spring snow depth has declined by 40% over the past 40 years. It's believed that similar losses of spring snow are happening across the Australian Alps in the south-east corner of the country.
Meteorological data for 2006 showed that snowfall in Kosciuszko National Park highlands was among the three worst on record. The 2006 spring thaw was one of the earliest and quickest ever experienced.
Ecologists are worried because the warming climate and reduced rainfall look set to wreak havoc on the fragile ecosystems of Australian alpine regions. The local ski industry isn't too pleased either, since no snow means no snow business.
A 2003 report produced by Australia's national science agency, the CSIRO, found that ski resorts could lose a quarter of their snow in 15 years, and half by 2050. The worst case scenario is a 96% loss of snow by mid century. But these predictions may already be today's reality: snow cover in some areas in 2006 reached the lower end levels that the CSIRO report had estimated as likely for 2020.
The problem is multifaceted. As the climate changes, the winter rain systems are expected to lessen; this means the chance of snow falling decreases further — even if it is cold enough to snow.
There's hope among the big resorts that, if they double their snow-making, they should stagger through to 2020. However, their capacity to produce artificial snow is limited by their access to water, the basic material for the snow-making. Less rain means less snow, be it natural or artificial.
Even the renowned ski-fields of Europe are facing a similar predicament, with rising temperatures threatening the future of ski resorts in the French Alps below 1,800 m. The recourse to snow machines to compensate for a reduced volume of natural snow in recent years is placing mountain water resources under pressure.
10. Mediterranean Coast, Spain
MAJORCA, IBIZA AND THE COSTA DORADA (or Golden Coast) of the Spanish Mediterranean: they're names synonymous with summer, sand and salsa.
Each year, about 100 million people head for the Mediterranean Sea with leisure on their minds and dollars in their pockets.
It is the world's biggest tourist movement — but this mass traffic of people could be a postcard memory within decades. Climate experts are forecasting that the Mediterranean could quickly become too hot for summer tourism, while higher sea levels transform the region by 2030.
Higher temperatures may already be here to stay: this summer saw Spain swelter, with 20 cities posting record monthly temperatures. The north western Spanish city of Ourense endured a record 41.4˚C.
Even if the heat doesn't deter the hordes, there's a real possibility that the beaches may not be there to welcome sizzling bathers. With rising sea levels, the beaches are disappearing.
Hotel owners in the southern Costa del Sol have already asked for permission to bring in their own sand as their beaches begin to shrink. It's expected that the Mediterranean coast will lose an average of around 10 m of beach by 2050.
Fewer tourist dollars is anticipated as just one of a legion of curses that will afflict the countries bordering the Mediterranean in a warming world. It's believed they will also suffer an increased risk of severe water shortage, forest fires, loss of agricultural land and an influx of potentially invasive plant, insect and animal species from the south.
SO, THERE YOU HAVE IT: 10 of the world's greatest travel wonders, the top destinations of our time, that will likely be adversely affected by climate change in coming years and possibly lost altogether.
Be it increasing temperatures, rising sea levels, increased storm activity or reduced habitat, some of the planet's iconic attractions - if not headed for history - will certainly become a shadow of their former selves. In a world undergoing climate change, little is certain and nothing is forever.
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David Salt is a science journalist in Canberra.
