<human>:  How has the climate changed in the last 20 years?
<bot>: In the last 20 years, the global climate has been changing rapidly due to increased levels of greenhouse gases in the atmosphere. The global average temperatures have been rising, causing more extreme weather patterns, more powerful hurricanes and more frequent and intense heat waves. Additionally, sea level rise, melting glaciers and changing rain patterns have all been observed, leading to more droughts, floods, and other consequences. In general, the world has become a more unpredictable and dangerous place.