1998 was also the warmest year on record, and probably in 1,200 years. No single weather event or year proves humans are warming the planet. But a powerful scientific case is emerging based on studies of long-term trends, some of the most compelling issued in just the past year. Glaciers are melting, polar sea-ice is shrinking, ice shelves are breaking up, and permafrost is melting. Severe drought and drenching rainfalls are afflicting increasing swaths of the planet.
Heat is devastating ecosystems from tropical corals to Alaska forests.
In other words, said AGU, the scientific record shows us that atmospheric CO2 levels and climate are closely linked. Certainly something is heating the globe. The century's 10 warmest years have all occurred since 1983, seven of those in this decade. A new National Science Foundation study based on natural records such as tree rings, ice-cores and corals finds the last decade of the millennium has been its hottest. That makes what we're now seeing more unusual, and more difficult to explain without turning to a 'greenhouse gas' mechanism.