Scientists who assess the planet’s health see indisputable evidence that Earth has been getting warm in some cases rapidly. Many believe that human activity, especially the burning of fossil fuels and the resulting collection of greenhouse gases in the atmosphere, have caused this warming trend. In the last decade scientists have documented record-breaking average annual surface temperatures and have observed other signs of change all over the planet: in the distribution of ice and temperatures of the oceans.
Ice is changing everywhere on the Earth. The famous snows of Kilimanjaro have melted more than 85 percent since 1911. Glaciers in the Indian Himalayas are retreating so fast that researchers fear that most central and eastern Himalayan glaciers could actually disappear by 2035. Arctic sea ice has thinned so much over the past half century, and its extent has declined by about 10 percent in the past 30 years. NASA’s repeated laser altimeter readings show the edges of Greenland’s ice sheet shrinking continuously. Freshwater ice breakup in the Northern Hemisphere now occurs nine days earlier than it did 150 years ago, and autumn freeze-up ten days later. When temperatures rise and ice melts from the icebergs, more water flows to the seas from glaciers and ice caps, and ocean water eventually warms and expands in volume. This combination of effects is the most important factor in raising average global sea level between ten and twenty centimeters in the past hundred years, according to the Intergovernmental Panel on Climate Change (IPCC).
There are absolutely no words to describe how much, and how fast, the ice is changing. Researchers predicted long ago that the most visible impacts from a globally warmer world would occur first at higher latitudes: rising sea temperatures air, earlier snowmelt, later ice freeze-up, reduction in sea ice, worse erosion, increase in storm intensity. All these impacts have been documented in Alaska. “The changes observed here provide an early warning system for the rest of the planet,” says Amanda Lynch, an Australian researcher who is the chief investigator on a project that works with Barrow’s residents to help them implement scientific data into management decisions for the city’s infrastructure.
Ian Hall, also of Cardiff University, who co-directed the scientific expedition, indicates that the results can contribute to understand how the Earth’s climate will respond to anthropic changes. Similarly, Jiménez Espejo, noted that last year, during an expedition aboard Hespérides, the French Navy research vessel, they were able to observe the various huge icebergs that had just broken into several pieces next to the islands of South Georgia. Ocean warming may cause the trajectories and the melt patterns of these large icebergs to change in the future, in a way affecting the currents and, therefore, our climate and the reliabilty of the models that scientists can use to predict it.