The 2018 Winter Olympic Games in South Korea's Pyeongchang are set to officially begin with Friday's opening ceremony.

But the current rate of global warming suggests that past Winter Olympics sites may no longer be viable as hosts in future.

Weather conditions, including temperatures, natural snowpack and days conducive for making snow, have a serious effect on the quality of the Games.

For example, Vancouver (2010) saw snow melting quickly before the Games began. Four years later, during the Games in Sochi, temperatures reached 20 degrees Celsius.

While Pyeongchang is expected to be extremely cold for the opening ceremony, the long-term trends show a shift away from the low temperatures associated with the Winter Games.

Global temperature trends since 1924, when the first Winter Olympics were held, show that the month of February has already warmed an average of 1.01C worldwide - all but four Winter Olympic Games have taken place solely during that month.

As previously reported by Climate Central, only six of the 19 past Olympic host cities will be climatologically reliable for hosting the Games by the end of the century, in a business-as-usual emissions scenario.

On average, previous host cities will see 2.1C of warming by the 2050s and 4.4C of warming by the 2080s, under that scenario, and 1.9C and 2.7C of warming, respectively, with significant emission cuts.

Additionally, northern hemisphere snow cover extent is declining and glaciers are retreating.

Not only is this bad for winter-based economies, as well as the sporting events themselves, but it also makes reliable training locations difficult for athletes to find, forcing them to travel further to prepare for competition.

In the United States, some ski seasons are forecast to be 50 percent shorter by 2050 and 80 percent shorter by 2090, and the effect of this extends beyond professional athletes.

Winter sports generate $72bn a year in the US and support nearly 700,000 jobs.

An updated report on the economics of the winter sports industry and the effects of climate change is expected by the Protect Our Winters group in the coming weeks.

Amid the growing threat, many ski resorts around the world have been investing in sustainability efforts to mitigate and minimise their contribution to climate change, by reducing waste and using renewable energy.

Article by Climate Central and posted on Impacts, Climate, Extremes, International