I am not a scientist and I can only share my observations, insights and experiences on this topic. Based on what I have seen in the mountains, I would have to say yes, climate change is having a negative impact on safety in the mountains. After all, most mountains are simply large piles of rock held together by ice. When this ice melts, the force of gravity takes over and the mountain starts to shed its “skin”.
This year on Everest was reported as a “crazy weather” year. Most years on Everest can be described as such, but this year seemed to be even crazier than usual. The winter of 2012 was a dry one for the Everest region and the mountain saw very little snow. The warm temperatures of spring arrived earlier than normal and as the first teams were arriving at base camp in early March they could tell this was going to be an odd year. Odd on Everest is usually not a good thing.
“Dry” is how it was described. There was a lack of snow at base camp and this caused concern for what the conditions would be like higher on the mountain. The temperatures were also much warmer than usual, and this was causing a rapid melting of what snow and ice there was.
The implications of this on Everest are many. For starters, climbers must negotiate their way through the Khumbu Ice Fall, a labyrinth of towering ice blocks, to make their way to Camp 1. This maze of broken ice is extremely unstable at the best of times and has claimed many a life. As this mass of snow and ice slides off Mt Everest, large blocks dislodge, tumble and crash. If a climber happens to be in the ice fall when one of these behemoth blocks of ice decides to fall over, the end result is unavoidably tragic.
The Khumbu Ice Fall is one of the scariest sections on Everest to climb and yet it is unavoidable when climbing from Nepal. Climbers will pass through this section of the mountain 6-12 times and the Sherpa climbers will pass through it almost daily as they transport loads to the upper camps on the mountain.
To safeguard passage through the ice fall, climbers depart base camp in the middle of the night when temperatures are at their coldest. The theory is that the freezing temperatures will help “bond” the blocks in place. As the sun warms the air later in the day, these bonds start to melt and the ice fall becomes very unstable and a veritable mouse-trap maze.
As the first Sherpa and climbers were making their way through the ice fall this season they noticed that this year was different. The ice fall had an even more unstable and menacing personality than normal. Ice block collapses were common, and the constant movement in the ice fall made the route ever-changing and treacherous. The Sherpas were scared; and when the Sherpas get scared, the climbers take notice. Discussions began about the viability of safely climbing Everest this season.
Although the snowfall had been low, avalanches were still a great threat. Avalanches in the mountains can come from two main sources. The first is an unstable buildup of snow on a moderately sloping face. When the bond between the snow layers breaks the avalanche roars down the mountain. The second source is from what is called hanging seracs. These are massive blocks of glacial ice that cling to the side of the mountain. At some point gravity always wins this tug of war and the blocks fall with devastating force. Once again, warm temperatures cause the foundations of these seracs to weaken and eventually to fail. The Ice Fall and Camp 1 are surrounded by huge, imposing walls covered with avalanche potential.
Traditionally, climbers have been most afraid of the West shoulder of Everest. They have slowly migrated Camp 1 away from this and closer to what was considered the relative safety of the steep face of Nuptse. This year, the odds were against the climbers and a massive avalanche roared off Nuptse and steamrolled into Camp 1 destroying tents and injuring several climbers.
Meanwhile above Camp 2, the Lhotse face was firing rock and ice missiles at unsuspecting climbers. The Lhotse face has long been feared by climbers, but is usually stable from a rock fall and avalanche standpoint. This year the snow was not there to act as a bonding agent. As the jet stream parked its self over the mountain, ferocious winds began to dislodge rocks at frequent intervals. Anyone who ventured onto the face was playing Russian roulette and many climbers lost. Nobody was killed, but bones were broken and stitches were sewn.
The Yellow Band is an outcropping of rock just above Camp 3 and must be traversed on the way to Camp 4. Beyond that, there is another rock band that guards the way to the South Summit. Snow and ice are much easier to climb while wearing crampons than rock. Ascending these rock sections with crampons on is comparable to walking across a marble floor with metal golf spikes on. Your traction is limited at best. Due to the low snow these sections would be more difficult than usual.
All of these issues can be chalked up to climate change, and they were weighing heavily on the minds of the climbers. One expedition leader who was supporting a large group of over 100 climbers and Sherpa made the bold move to pull the plug and cancel the all his expeditions on Everest, Lhotse and Nuptse. This was an unheard of move and it shook the community. Some agreed and some did not, but ultimately the decision was made in the face of danger with an extreme concern for safety.
Additionally there is photographic evidence that shows the retreat of the great glaciers of Everest and mountains around the world. There is no doubt in my mind that the climate is changing and that it is having dangerous consequences in the mountains.