Scientists now regard the warming of the Earth's climate system as unequivocal, and most scientists believe that this warming is due in large part to human activities, principally the injection of carbon dioxide into the atmosphere through the burning of fossil fuels that has accompanied industrialization. Warming during the l00 years from 1906 to 2005 totaled 1.3 degrees Fahrenheit (0.74 degrees Celsius). The International Panel on Climate Change reported that the average global temperature for the years 2090-99 will likely be a 3.2 to 7.2 degree Fahrenheit (1.8 to 4 degrees Celsius) increase from the 1980-99 global average. Nine of the 10 warmest years in the instrumental record (since 1850) have occurred since 2001- the exception being 1998, the third-warmest year on record. The year 2010 tied with 2005 as the warmest on record. Moreover, analyses of data such as tree rings, ice cores, growth of corals, and historical records indicate that at least in the Northern Hemisphere, the last 50 years were probably the warmest period in at least the past 1,300 years. In the 20th century, sea levels rose 6.7 inches (0.17 meters) and it is believed with high confidence that this exceeded the rate in the previous century. The continuing rise of sea levels has alarmed the scientific community, and planning for adaptive measures is underway in many coastal cities. (New York Times ‘Guide to Essential Knowledge’)