In this video, a spokesperson for the National Climactic Data Center describes the methods of using satellites (originally designed for observing changes in the weather) to study changes in climate from decade to decade. The video clearly illustrates the value of satellite data and begins to address connections between weather and climate.
This video features research conducted at University of Colorado's Institute of Arctic and Alpine Research, which studies isotopes of hydrogen trapped in ice cores to understand climate changes in the past.
This gallery of ten temperature graphs shows global temperatures on different timescales from decades (recently measured temperatures) to centuries (reconstructed) to millions of years (modeled from ice cores).
This short video from Climate Central explains the technology used to monitor changes in Arctic sea ice. Long-term tracking (since the late 1970's) shows Arctic sea ice has been on a steady decline and this could have significant implications for global temperatures.