With the global population now well over seven billion there are few remaining parts of the world relatively untouched by human activity. We assess the current state and future prospects of five final frontiers: rainforests, Antarctica, the Arctic, the deep sea and space.
Antarctica is the coldest, highest, driest continent – and the one which bears the smallest footprint of human occupation. It is also the only continent designated as a “…natural reserve, devoted to peace and science”.
So how is Antarctica faring? What are the human impacts on this, the last of continents, and what might the future hold?
Climate change impacts
By far the greatest human impact on Antarctica and the surrounding Southern Ocean are the effects of climate change. In some regions, most notably the Antarctic Peninsula, these impacts are clear: warmer ocean temperatures, loss of floating ice shelves, melting glaciers, changes in the coverage and seasonality of sea ice, and environmental and ecological responses such as changes in the distribution of penguin species.
In other parts of Antarctica the impacts are more subtle: changes in sea ice distribution, below-surface melt of floating ice shelves, increased precipitation and changes in the profiles of ocean currents.
Some of these “subtle” changes though, are profound. The measured decrease in the salinity of Antarctic Bottom Water (AABW) and over 50% decline in its volume signal great changes to the global ocean overturning circulation.
Ocean acidification, caused by the oceans' absorption of carbon dioxide, has already had a measurable impact on some Southern Ocean organisms. The big unknown is the potential for these marine species in the Southern Ocean to adapt to inevitable changes in the acidity of their environment.
In the 2011-12 tourist season, 26,519 tourists travelled to Antarctica. The figures provided by the International Association of Antartica Tour Operators show that this represents a significant decline compared to historical numbers which peaked at around 45,000 in 2007-08 (before the global economic crisis). Tourism numbers, though, are likely to steadily increase in coming years. Visits to the continent from tourist vessels (21,131 people in 2011-12) are usually brief and restricted to a relatively small number of sites. By far the bulk of this tourism occurs in the Antarctic Peninsula region.
The Antarctic Treaty’s Committee for Environmental Protection (CEP) recently concluded a study on how tourism interacts with the Antarctic environment. Although data on tourism impacts is limited, the weight of available evidence indicates that, apart from obvious track formation, and localised destruction of some moss beds, tourism is not having a great direct measurable impact, even in the most heavily visited areas.
At the scale and intensity of current Antarctic tourism, the impacts of human activity are more likely to be indirect - such as through the introduction of alien species or diseases to wildlife. However a recent study indicates there is a greater risk of introduction from national Antarctic programs than from the tourism industry.
National Antarctic science programs
Even though the peak summer and winter occupation of Antarctic research stations are around 4000 and 1000 people respectively, scientists spend much more time on the continent than tourists. National program activities involve a much greater level of infrastructure and operational support, including permanent stations, wharf and air facilities, fuel, waste management and field outposts.
There are ongoing impacts of historical research activity in Antarctica. These are usually the legacy of past waste management practises: abandoning buildings, vehicles and equipment; and leaving waste material, including oils and other organics and heavy metals in dumps or letting them float out to sea on ice. Thankfully these practises are a thing of the past. But while the volumes may have been small on a global scale, the significance is magnified by the location of many of these legacy sites in rare ice-free coastal environments.
The current management of national activities is a far cry from the past practises, but still provide the biggest pathway for human impacts on the continent and its fringes.
Eternal vigilance and control over the supply chain of national programs is the key to ensuring that the very research that’s conducted in Antarctica is not its greatest direct threat.
Marine resources and fishing
The decimation of the populations of great whales and some seal populations in the 19th and 20th centuries represent the biggest biological impacts of human activity in the Southern Ocean. While many of these species have begun to recover (some, like fur seals, most spectacularly) others, such as the Blue Whale, are only a small fraction of their pre-exploitation numbers.
But Antarctica has the largest underexploited fishery in the world - the krill fishery. Increasing human populations and the pressure on oceans around the globe will result in increased interest in the Antarctic krill fishery. Currently fished at around 200,000 tonnes per annum, the krill fishery has a potential precautionary catch limit in the millions of tonnes.
There are some signs that changes around the Antarctic Peninsula region have resulted in changes to the distribution of krill, and also to the behaviour of krill fishers. Any ramping up of the krill fishery will have to be carefully managed to ensure that localised impacts are avoided and the integrity of the Southern Ocean ecosystems maintained – it would be foolish indeed to squander the opportunity to manage this fishery for both the ecosystem and humankind.
Much media and academic commentary has been directed at Antarctica’s potential as the last remaining unexploited mineral province on the planet. There is an indefinite and legally binding prohibition on mineral exploitation in the Antarctica Treaty area as a direct result of the negotiation of the Madrid Protocol. But speculation about the intention and motives of countries with respect to mining in Antarctica is likely to remain a feature of Antarctic discourse.
However for both practical and political reasons, mineral exploitation in the Antarctic, including for oil, is unlikely in the foreseeable future.
The future of Antarctica
Antarctica is blessed by its remoteness, harshness and political history. The bulk of Antarctica is a long way from anywhere and human access and presence is restricted. It is a continent at the bottom of the globe, surrounded by a cold ocean which will slow the progress of regional warming. The Antarctic Treaty System established on principles of peace, cooperation and science provides a governance regime which has the power to balance the competing interests of human pressure against the protection of the environment.
But that does not mean the future is clear sailing. Measures to incorporate modern thinking and science into a comprehensive system of marine protected areas have been slow to be adopted, and climate change has already locked in changes to Antarctica that will endure even if the world takes significant steps in the near future to curb greenhouse gas emissions.
Managing human impacts as the climate opens up new opportunities for alien species to become established will also be a major challenge for the future, as will the systematic and precautionary management of the harvesting of marine living resources.
The world should ensure that Antarctica remain the last of continents, largely free of the ravages wrought upon other continents. And it should support and strengthen the Antarctic Treaty System to carry out its mandate to keep Antarctica a natural reserve devoted to peace and science.
Next: the Arctic.