5.1 Historical warming of the earth.

5.1.1Causes.

5.2 Greenhouse gases in the atmosphere.

5.3 Solar variation theory.

5.4 Expected effects.

5.4.1 Spread of disease.

5.4.2 Financial effects.

5.4.3 Biomass production.

5.5 Opening up of the Northwest Passage in summer.

5.6 Dangerous global warming.

5.6.1 Ocean acidification.

5.6.2 Relationship to global dimming.

5.7 Pre-human global warming.

5.8 Pre-industrial global warming.