We can now remotely sense almost every inch of the Earths surface, above or below the water-line. The topography, vegetation, wildlife and human populations of our planet are, by and large, documented. Of course there are discoveries still to be made animals to be found and identified, some tribes remaining un-contacted in the depths of the shrinking Amazonian forests, areas of the Earths surface that haven't been touched by human foot at least not in written record.
But, lets face it, we can identify planets that may be suitable for life, we've scanned the surface of the Moon, Mars and asteroids, we have imaging satellites in the sky and sensing devices in the oceans. Haven't we explored it all? Well, the answer is no because the world of caves remains largely unexplored. There are huge areas of the Earths surface that have never been exposed to light, let alone seen a human presence. Its just that they lie hidden, underground. Caves are the only environment left on Earth that truly remains for original exploration. Caves have long associations with humanity. For our ancestors they provided shelter and space for ritual, and in many parts of the world, people still live in caves or use them to house livestock, mature cheeses or provide storage.
But the deep cave environment has always been an area of mystery, of the unknown, of hidden dangers and great beauty. Given that that's the case, why doesn't cave exploration have a higher profile? Well, marketing probably has something to do with it - cavers dont tend to have the sexy gear appeal of lycra-clad beauties on a climbing wall, dont provide good models for shiny new Gortex cagoules or the latest rucksacks. Cavers have a reputation as scruffy, somewhat eccentric individuals, wet and caked in mud. So if you are interested in media glory, go somewhere else and don't bother reading on What are caves and where are they? Most people know what caves are but they may not appreciate their variety. In the UK, as elsewhere, they are found in our limestone areas where, over thousands of years, rainwater has seeped into the rock, gradually eating it away to form conduits through which the water can flow to a lower level.
As long as the conduit remains full of water, the rock will be eaten away more or less equally in all directions and so a tube is formed. But if the water level drops, or the rock is thrust up by some geological movement, the upper part of the conduit may become full of air and only the bottom of the tube carries the water which continues to cut downward, forming a trench. Classically, the two can be seen together in a passage cross-section that looks like an old fashioned keyhole. The calcium carbonate that formed the rock and was dissolved by the water as the passage formed can come out of solution again to form stal - stalagmites, stalactites and flowstone formations, often of great beauty and complexity, and coloured by minerals in the rock and soils above.
This, of course, is a simplification, the water can carry rocks and sediment which abrade the walls away, water can flow upwards or vertically downward, passages can collapse or consolidate. The net result can be a complex maze of passages and chambers, ranging from the ridiculously small to the unbelievably large. Sarawak Chamber, the largest natural void in the world, in Borneos Gunung Mulu National Park, could accommodate 42 Boing 747s or 16 of the old Wembley Stadiums. (Youd have a hell of a job flying the planes up the entrance passage, or playing football on a sloping floor of boulders the size of cars, but you get the idea) and there are caves in China that are so big that clouds form inside them. So, in most areas that have limestone you will have a chance of finding caves.
But the occurrence and size of those caves will depend on multiple factors rainfall, vegetation (CO2 from plants make the water acidic which speeds the process of cave formation), temperature etc. And the accessibility of the caves will depend on factors like vegetation (finding entrances in rainforest can be a challenge), topography, land-ownership, local beliefs and politics, of course. Its worth noting that somewhere around 70% of the worlds limestone is in China, a country in which European cavers have only been operating since 1985. But caves are found in other types of rock too. Most particularly in some volcanic areas where slow flowing lavas crust over as they cool, while the hot lava continues to flow on in discrete channels underneath.
When the channels empty they leave cave passages, often very long and well decorated with stals formed by hot gases causing the roof to re-melt and drip or the hot lava leaves rope and pillow-like formations on the floor. Caves are a home to other species too they form an often rich biological environment, although their residents may not be easily spotted, particularly in temperate regions where population levels are low. Stating the obvious, there is no sunlight in a cave to provide an energy source for life, no growing green plants; so the energy has to be imported. In temperate areas this is most often in the form of detritus carried in by streams, whilst in the tropics, caves can house huge populations of bats and cave swiftlets the latter being small birds that echo-locate like bats and nest deep in the caves (they provide the raw material for birds nest soup translucent material made from dried bird spit). The droppings from these animals, as well as their bodies when they die, provide a food source for others which, in turn, fall prey to predators.
Cave animals are stereotypically slow moving, blind and white adaptations to an energy poor environment. Caves often form the habitat for relict species, the descendants of animals that took refuge in caves during periods of climatic change; cave biology is a well-established scientific discipline. Some caves provide even more peculiar conditions with life forms that rely not on imported energy derived from the sunlight outside but on chemical energy from upwelling waters rich in sulphur. And some caves owe their existence to this phenomenon, eroded not by flowing streams but by acidic gases. Of course, it should go without saying that an environment with this level of complexity is fragile. Blundering about in caves can result in the destruction of formations that took tens of thousands of years to form; unthinkingly placing dirty hands on clean stal can ruin it forever, walking on stal crusts, the edges of rimstone pools or mud formations can destroy them; leaving food scraps or human waste in caves can destroy the cave animals (they eat the unexpected feast, breed and then there isnt sufficient food to support the new population levels and they all die).
Cave conservation is important. So environments with unknown animals, places that have never been exposed to light, unexplored, unmapped, unknown and untouched by our species - the only true exploration frontier. Why would you want to waste your time trying to be the first person to pogo-stick down Everest or the youngest person to traverse the Grand Canyon on a paper aeroplane these things may be adventure but they're not exploration. Where to start? Well, its not wise to go off to Central Asia with a candle and a ball of string and start exploring. You may have an interesting time but you either wont get far or you wont come back. Caving is considered by insurers to be a high risk activity. Those of us who are active cavers would contest that view and point out that accidents from, say, horse-riding or rugby are much more common and often much more serious. But the media likes a good story, theres nothing better than a cave rescue to fill the pages on a dull day and there are very few insurance people or journalists with direct experience of caving and so the image is hard to dispel. (In fact, many cave rescue call outs are not to cavers at all but to trapped livestock, walkers and the occasional plonkers with balls of string and candles). Most people start caving with a club or, at least, a group of experienced friends.
Caving can be very technical the techniques of surmounting underground obstacles have a lot in common with climbing but cavers tend to be more diligent in the way they handle their ropes. Vertical drops of hundreds of metres demand respect and careful rigging a loaded rope will part on contact with a sharp edge so its important to ensure that ropes are positioned and belayed carefully to avoid this risk; these techniques need competent instruction and practice. Even on a short pitch (vertical drop) a mistake can have serious consequences, perhaps trapping a party underground with a casualty. Traditionally, cavers learnt from nanny, acquiring experience and skill on repeated trips with mates but the danger of this approach is one of incompetent cavers teaching other cavers to be incompetent in their turn. A number of professional organisations offer training courses which can provide high quality instruction, initially in safe controlled environments, before going at it for real. A mistake in a wild cave can be serious you cant get a helicopter rescue. Whats needed? In addition to the skills and a body of experience, youll need the gear.
This depends on the type of caving you intend to do. Caving may not have the lycra-clad appeal of rock climbing but equipment has got steadily more sophisticated in recent years. This ranges from clothing (thermal undersuits, shorty wetsuits, rip/water resistant oversuits), to SRT rigs (the equipment for Single Rope Techniques ways to descend/ascend vertical drops using one rope, rather than, say, a ladder and a lifeline) and, particularly in recent years, lighting. 40 years ago carbide lights were common and until about 10 years ago they were universal on big caving expeditions carbide could almost always be locally sourced , whereas charging facilities for electric lamps could be problematic. But in the last few years LED technology has accelerated and, with it, lamp technology. The most sophisticated caving lights today will cost upward of 600. Knee pads can be really useful in caves with extended crawling sections (there are plenty of older cavers with knee problems). Footwear is a matter of personal preference - decent boots or wellies with good soles. For the UK, you can very often get away with grots old clothes at least until you are sure you want to pursue this activity. One thing you wont want to do without is a good helmet; caves are much harder than your head.
Don't think that just because we live in a crowded island all possibility of finding new cave has long since been exhausted: it isn't so. OK, you are unlikely to find a new cave entrance and just walk into unexplored passage but all around the UK there are projects to get into cave passage that has been lost perhaps the entrance has been filled in by a farmer in the past, or filled in with sediments during some flood episode long ago. There is an entire sub-discipline of digging, with regular outings to favourite sites for a few hours work, followed traditionally by an RR session in the pub afterwards. As recently as November 2011 two teams of cavers made a connection between the Lost Johns and Notts Pot caves in the Yorkshire Dales, successfully creating the final link in the Three Counties System which now has a combined length of around 100km. This was the culmination of 50 years of steady effort and there is still more to find in this cave system. Exploration remains a possibility in the UK but there are plenty of areas of the world in which unexplored caves remain and British cavers have been active in almost all of them.
The range of possibilities is extensive, from the deep, cold alpine cave systems of Europe to the huge caves of Borneo, China and Vietnam; from the bare uplands of Northern Greece to the forests of Burma, caves remain to be found all over the world. If you are proposing to undertake original exploration you will, like any proposed expedition, need to do thorough research to ascertain what the prospects are for new discoveries in terms of geology and climate, whats been done before and by whom and what type of caves are likely to be encountered the equipment and skills required for deep vertical alpine systems are different from large, horizontal river caves. And unfortunately you are very unlikely to get away from bureaucracy. Most countries have established procedures for requesting permission to undertake exploration, even if this only involves formally contacting local cavers; generally speaking, the more exotic the location, the bigger the bureaucratic hurdles.
You'll also need a plan B in case of a major incident because most countries, unlike the States and Europe, don't have established, competent cave rescue organisations so you will need to have the equipment and expertise to mount a rescue yourselves and get your casualty to medical care. In somewhere like the highlands of Papua New Guinea, this could be a real challenge! And you need to ensure that your insurance covers you for the expenses of self-rescue because most insurers assume that you will be sorted out by a professional rescue team.
More information UK: The British Caving Association has good advice website for new cavers, with links to many of the UK caving clubs: http://www.trycaving.co.uk/ and the Associations main site has lots of useful information: http://www.british-caving.org.ukSimilarly, the British Cave Research Association has a wealth of information on its site, including funding. BCRA maintains an extensive library which holds reports from many expeditions; its publications provide summary accounts of discoveries and are a useful source of reference, as are the BCRAs special interest groups and its Foreign Secretary.http://www.bcra.org.uk/ US: TheNational Speleological Society