Media Construction of Global Warming

PowerPoint Slide Show, Lesson 2

Global warming: Fact of Myth

Are recent trends in global temperature

unprecedented in our climatic history?

How do we know whom to believe when scientists

disagree on the answers to highly technical and

potentially cataclysmic questions?

Two ice core records created by independent research teams from different sites in Antarctica.

Surface air temperature and its changes over the past 150 years based on compiled surface temperature measurements.

Arctic temperature proxies for 1600-1990 from a compilation of paleoclimate records from lake sediments,

tree rings, glacier ice cores, and marine sediments.

Temperature-sensitive paleoclimatic multi-proxy data from 17 sites worldwide. Proxy sources include

tree rings, ice cores, corals, and historical documents.

Reconstruction based on multiple tree ring and ice core data sets.

Temperature variations from a northern tree-ring density network.

Proxy data used: tree-rings, ice cores, and historical documents.

Graph showing six different temperature reconstructions based on a variety of proxy data sources, with observed temperature

averages (through direct measurement) on the same set of axes.

The Hockey Stick Curve

The year-by-year (blue curve) and 50-year average (black curve)variations of the average surface temperature of the Northern Hemisphere for the past 1,000 years. (From IPCC’s Third Assessment Report)

Global Warming:

The current and unprecedented rise in the Earth’s temperature.

Is global warming

a fact or a myth?