Michael Mann's Blog

The Rise and Fall of the "Atlantic Multidecadal Oscillation"

Two decades ago, in an interview with science journalist Richard Kerr for the journal Science, I coined the term the "Atlantic Multidecadal Oscillation" (the "AMO" for short) to describe an internal oscillation in the climate system resulting from interactions between North Atlantic ocean currents and wind patterns. These interactions were thought to lead to alternating decades-long intervals of warming and cooling centered in the extratropical North Atlantic that play out on 40-60 year timescales (hence the name).

On The Importance of Diversity in Climate Communication

In light of recent social media posts and conversations I've had with colleagues, I want to take this opportunity to make a statement about the importance of lifting the voices of women, people of color, and other voices that have been marginalized in the world of science communication, including the discourse over climate change.

On Tropical Atlantic Warmth and Hurricanes

A new study just out in Science attributes the unusually active 2017 Atlantic hurricane season to tropical Atlantic warming. Furthermore, it attributes that warmth to human-caused climate change (a combination of increasing greenhouse gas concentrations and sulphate "aerosols" from industrial pollution).

Climate Change Denial in the Age of Trump

With a climate change denier in the White House, climate denialism has reached a new low point in America. Indeed, my co-author Tom Toles and I have devoted a whole new chapter to the matter ("Return to the Madhouse: Climate Change Denial in the Age of Trump") in the new paperback edition of our book The Madhouse Effect (now available for pre-order).

A Sensitive Topic

There is a quantity known as the "Equilibrium Climate Sensitivity" or "ECS" that serves as a traditional measure of the warming effect of greenhouse gases. The ECS characterizes the total warming we would expect from a doubling of the concentration of greenhouse gases (e.g. from the pre-industrial level of 280 parts per million to the 560 ppm level that would be expected by the middle of this century if we continue with the unabated burning of fossil fuels) once the climate system fully adjusts to this increase.