Intensified warming of the Arctic: Causes and impacts on middle latitudes

Global and Planetary ChangeJohn E. Walsh

Outline

• Current status update of Arctic

• Drivers and mechanisms of Arctic change

• Impacts on middle latitudes

• Conclusion

Degree (C)

Annual mean change of surface air temperature in the northern hemisphere over the last 50 years

Less IceLess reflective surface area

=

More heat absorbed and released by the ocean

Sea Ice Albedo Feedback

Less IceIncreased atmospheric moisture

Increases Downwelling radiation

Warms lower Troposphere

Water vapor/Infrared feedback loop

Atm

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(m

b)

Atm

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(m

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Atm

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