This story is part of CBC News special coverage of climate change issues in connection with the United Nations climate change conference (COP21) being held in Paris from Nov. 30 to Dec. 11.


3rd-largest icefield in the world

The Perito Moreno glacier, in Los Glaciares National Park, is part of the Southern Patagonian Icefield, the third-largest reservoir of fresh water in the world. The Antarctic and Greenland ice sheets are the first- and second-largest frozen reservoirs respectively.

COP21 Patagonia Argentina shrinking glaciers Nov 30 2015

Certain parts of the 250-square-kilometre Perito Moreno glacier take on a bluish hue (thanks to light refraction) at certain times of the day. (Mario Tama/Getty)

COP21 Argentina hikers on Perito Moreno glacier in Los Glaciares National Park Nov 30 2015

Hikers trek up the sediment-stained slopes of the Perito Moreno glacier on Nov. 30. (Mario Tama/Getty)

Patagonia Argentina COP21 climate change Perito Moreno glacier Nov 30 2015

Perito Moreno glacier is named after 19th-century Argentine explorer Francisco Pascasio Moreno, who played a major role in keeping the southern sliver of the continent from becoming part of neighbouring Chile. (Mario Tama/Getty)

Bleeding edge of climate change

Located in Argentina's Santa Cruz province, most of the almost 50 large glaciers in Los Glaciares are in retreat and have been shrinking steadily over the past 50 years due to warming temperatures, according to a report by the European Space Agency (ESA), which monitors the effects of climate change from above.

COP21 Argentina glacier runoff Heim glacier Los Glaciares National Park Nov 28 2015

Run-off cascades from the edge of Heim glacier, in Los Glaciares National Park, on Nov. 28. (Mario Tama/Getty )

Patagonia Santa Cruz COP21 climate change Nov 27 2015 glaciers retreat

The icy tips of the Perito Moreno glacier reach high above the Brazo Rico, or southern arm, of Argentino Lake on Nov. 27. ( Mario Tama/Getty)

Patagonia Perito Moreno glacier Nov 27 2015

The United States Geological Survey (USGS) reports that over 68 per cent of the world's freshwater supplies are locked in ice caps and glaciers. (Mario Tama/Getty)

COP21 climate talks underway in Paris

On Monday, 150 world leaders — including Prime Minister Justin Trudeau — and negotiators from nearly 200 countries gathered for the climate change conference talks in Paris and got down to the work of hammering out a deal to slow climate change.

COP21 Patagonia Perito Moreno glacier melt Nov 27 2015

Huge amounts of pressure from the moving bulk of glacial ice lead to spectacular ruptures like this one, photographed on Nov. 27, when chunks on the edge of the ice sheet calve off into Argentino Lake. (Mario Tama/Getty)

COP21 Patagonia Perito Moreno glacier retreat Nov 27 2015

Oceans away and in another hemisphere from Patagonia, the United Nations-led COP21 climate change conference began on November 30 in Paris. (Mario Tama/Getty )

The goal in Paris

Negotiators hope to turn a 50-page draft riddled with sticky issues into a binding, global agreement to cut greenhouse gas emissions to levels that will prevent a rise in average global temperatures by two degrees (the baseline being the Earth's surface temperature from around the end of the Industrial Revolution (useful records emerged around 1880).

Worst-case scenario

Ahead of the COP21 climate talks, the UN released a series of sobering forecasts predicting dire circumstances — including more severe storms — for the planet's plant and animal (and human) populations if the two-degree threshold is crossed.

COP21 Argentina Los Glaciares National Park horses Nov 27 2015

In the lowlands, below the glaciers, horses run wild in the grasslands at the foot of the Patagonian icefield. (Mario Tama/Getty)

COP21 Argentina Los Glaciares National Park Nov 26 2015

The projections are dire: glaciers will continue to shrink, heat waves will be more frequent and the oceans will get warmer and more acidic. A large majority of environmental scientists warn that if global temperatures rise by more than two degrees above pre-industrial levels, the consequences will be severe and, in some cases, irreversible. (Mario Tama/Getty)

Water, water everywhere

Disaster scenarios linked to a rise in global temperatures include the release of trillions of litres of water currently locked in ice sheets like the polar ice caps and Patagonia's icefield. The resulting sea-level rise would inundate coastal cities like Vancouver and Halifax, amounting to trillions of dollars in property damage, and worse.

With files from Reuters and Getty Images