December 30 - 2005 was the second warmest year on record, with record-breaking heat, drought, storms, and flooding worldwide, according to the United Nations' weather service. Severe long-term drought affected parts of Africa, and Europe received less than half its normal rainfall between October 2004 and June 2005. In India, unprecedented heavy rain and widespread flooding killed 18,200 people and affected more than 22 million. Warmer-than-average Arctic temperatures brought the extent of sea ice to an all-time low.

The 2005 Atlantic hurricane season tallied the largest number of storms and hurricanes in documented history. Hurricane Wilma was the most intense storm ever recorded. In the United States, a June heat wave broke more than 200 daily records in six Western states and logged the most consecutive days at or above 125 degrees Fahrenheit at Death Valley, Calif. Drier than average conditions led to the most active wildfire season that burned more than 8.5 million acres. Yet, nine states in the Northeast had their wettest Octobers, and Massachusetts had a record amount of snowfall.

The severe weather encountered this year has led to questions about the relationship of these weather patterns to the changing climate. Although scientists do not have enough evidence as yet to fully understand the potential connection, much work has been done on understanding and predicting weather and climate.

Several National Research Council reports deal with climate and weather. A 2003 workshop summary, Communicating Uncertainties in Weather and Climate Information, explores how best to communicate weather and climate information in five case studies, selected to illustrate a range of time scales and issues, from forecasting weather events to providing seasonal outlooks to projecting climate change. Climate Change Science: An Analysis of Some Key Questions sums up the current scientific understanding of climate change by characterizing the global warming trend over the last 100 years, and examining what may be in store for the 21st century and the extent to which warming may be attributable to human activity.

Improving the Effectiveness of U.S. Climate Modeling discusses how climate variability and change impacts society and why dealing with climate-related disasters requires the best possible information. The report offers a number of ways to enhance the effectiveness of climate modeling. Making Climate Forecasts Matter identifies research directions toward more useful seasonal-to-interannual climate forecasts and examines how we can use forecasting to better manage the consequences of climate change.

• Communicating Uncertainties in Weather and Climate Information: A Workshop Summary (2003)
• Climate Change Science: An Analysis of Some Key Questions (2001)
• Improving the Effectiveness of U.S. Climate Modeling (2001)
• Making Climate Forecasts Matter (1999)
• Summary of Climate Change Reports  

• UN World Meteorological Association
• National Atmospheric and Oceanic Administration