Wednesday, September 08, 2010

the most reliable measure of agw

A broader view of the role of humans in the climate system

Roger Pielke snr makes the point that ocean heat, measured in joules, is the most reliable measure of global warming. The ocean is the largest reservoir of heat change on Earth.

Temperature is not such a good measure. There is a time lag between radiative forcings and temperature, in the oceans or in the atmosphere. Unlike heat content temperature does not involve mass and so temperature is not an accurate measure of heat storage.

The study by Joshua Willis shows no significant change in ocean heat content over the period 2003-2008. Four years is a relatively short period of analysis but this finding does raise questions about our level of understanding and does contradict projections by the IPCC and James Hansen.

Pielke snr argues that regional factors such as drought, floods and hurricanes are independent of global radiative imbalance. However, these events are influenced by natural changes (El Nino,etc.), human alteration of the atmosphere, landcover and aerosols. These factors are regional, not global. The regional factors are more important than the global factor of increase in greenhouse gases.

Humans are altering the climate but the change is more diverse and complex than depicted by the IPCC. Policies that focus exclusively on CO2 reduction to control the climate are misguided. The IPCC is too radical about CO2 and too conservative about other ways in which humans are altering the climate.

1 comment:

Mark Miller said...

My understanding of this is limited, but what I got from my research on this was that surface ocean temperatures were more indicative of recent changes in heating, but they are of course influenced by heat stored at lower depths. From what I've heard from climate scientists heat can be stored in the oceans (at lower depths) for centuries. It takes a long time for a body of water to warm up, and it takes it a long time to radiate the energy it has built up. Considering the full volume of the oceans I find this conception conceivable. I remember one climate scientist suggesting that the heat being radiated by the oceans now could've been built up from the Medieval Warm Period.