1,817 square kilometers (702 sq mi) of the Alps covered by glaciers in 1876 had shrunk to 1,342 km2 (518 sq mi) by 1973. Forty percent of the glaciation in Austria has disappeared since 1850, and 30% of that in Switzerland. The scientists predict that if the current weather patterns persist, the glacial Alps will disappear by 2050. In 1860, the largest alpine glacier, the Aletsch was 3 km (1.9 mi) longer and the ice level 200 m (656 feet) higher. Experts say if global warming continues for a decade, in 70 to 100 years only alpine glaciers over 4,000 meters will resist this.