El gran debate sobre el calentamiento global (segunda parte)

The video discusses the natural climate cycles and historical warming periods, highlighting the medieval warming era. It addresses skepticism about global warming, emphasizing the need for direct temperature evidence. The video explains the use of climate indicators, like tree rings and ice sheets, to map historical temperatures, leading to the creation of the hockey stick graph by Michael Mann. Despite skepticism about the graph's accuracy, it shows no period in the last 1000 years as hot as the late 20th century. The video concludes with a consensus on recent warming trends.

What evidence is used to suggest that current warming might be part of a natural cycle?

• The Vikings' ability to farm in Greenland 1000 years ago

• The discovery of new fossil fuels

• The melting of polar ice caps

• The increase in volcanic activity

What are some methods used to estimate historical temperatures beyond the last century?

• Tree rings and ice sheets

• Ocean currents

• Seismic activity

• Satellite imagery

Who is the scientist known for creating the hockey stick graph?

• James Hansen

• Michael Mann

• Al Gore

• Stephen Hawking

Why do some skeptics question the accuracy of the hockey stick graph?

• It does not include data from the Southern Hemisphere

• It only represents 1000 years of data

• It shows a decrease in temperatures

• It was created using outdated technology

What is a key conclusion agreed upon by all graphs regarding the last 1000 years?

• The Earth's temperature has remained constant

• The medieval period was the hottest

• The second half of the 20th century was the hottest period

• The 20th century was cooler than previous centuries