TakeOnIt
Compare opinions of world leading experts and influencers.

Has CO2 passively lagged temperature in past climates?

Over the last million years, temperature and CO2 have been highly correlated, but with CO2 lagging behind temperature by several hundred years. The mainstream explanation amongst climate scientists is that Earth's orbital changes initiated warmings and coolings, and a positive feedback between temperature and CO2 amplified those changes. However, many climate skeptics interpret the lag during this period as evidence that CO2 can only be the effect rather than the cause of temperature change.

Implications to Other Questions

Does atmospheric CO2 cause significant global warming?
Has CO2 passively lagged temperature in past climates?

Experts and Influencers

Suggest Expert Quote (click to expand, no login required)
Agree
Experts In Climatology


Roy Spencer    Meteorologist
Mostly Agree
But it has often been noted that the Vostok CO2 record lags the temperature record by an average of 800 years, which is somewhat of a problem for Hansen’s theory. After all, if CO2 “took over” as the main driver of temperature, why do the CO2 changes tend to come after the temperature changes?
17 Jun 2009    Source


Experts In Science


Denis Rancourt    Physics Professor
Agree
CO2 increases may accompany temperature increases rather than causing them. Indeed, some high resolution studies have suggested that the temperature increases precede the CO2 increases.
27 Feb 2007    Source


Disagree
Experts In Climatology


RealClimate    Climatology Blog
Disagree
When I give talks about climate change, the question that comes up most frequently is this: “Doesn’t the relationship between CO2 and temperature in the ice core record show that temperature drives CO2, not the other way round?” ... In summary, the ice core data in no way contradict our understanding of the relationship between CO2 and temperature, and there is nothing fundamentally wrong with what Gore says in the film.
27 Apr 2007    Source


Intergovernmental Panel on Climate Change    (IPCC) Scientific Body formed by U.N.
Disagree
It is very likely that glacial-interglacial CO2 variations have strongly amplified climate variations, but it is unlikely that CO2 variations have triggered the end of glacial periods. Antarctic temperature started to rise several centuries before atmospheric CO2 during past glacial terminations.
01 Jan 2008    Source



Comments

Add Your TakeOnIt (click to expand, no login required)
0 Points      Benja      12 Jul 2010      Stance on Question: Mostly Disagree
Great strawman example in Denis Rancourt's quote:

"CO2 increases may accompany temperature increases rather than causing them. Indeed, some high resolution studies have suggested that the temperature increases precede the CO2 increases."

He presents well known CO2-temperature data as it was embarrassing and inconvenient news for the climatologists. He suggests that new improved studies undermine the core assumptions of climatologists, when in fact they confirm the assumptions based on earlier studies. Climatologists have in fact known about this lag since 1990:

"changes in the CO2 and CH4 content have played a significant part in the glacial-interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcing". More here.

In summary, for roughly the last 2-3 million years, as the Earth's orbit has oscillated, the change in sunlight has initiated the coolings and warmings that lead Earth in and out of ice ages. These temperature changes increase or decrease CO2 levels, which creates a positive feedback loop that amplifies the initial temperature change until a new equilibrium is reached (either an ice-age or an interglacial). This is 101 material.