Refining Climate History

You probably recall climate history charts of temperature and CO2 appear to show that rises in global temperature preceded rises in atmospheric CO2. This seems to be counter to today's theories that rising CO2 concentrations will cause a rise in global temperature, and thus provides fuel for the skeptics arguments against linking current rising CO2 levels to future global warming.

The title link to a Wall Street Journal article addresses this and details a new ice core effort in Antarctica aimed at refining  historical data to better clarify the relationship between global temperature and atmospheric CO2. The main questions with past data arise from proxy results for temperature, and with ice core dating. This new study aims to use oxygen isotope measurements to deduce global temperature (not new, but apparently being done in a more refined way), and adds several techniques for deducing ice core age. Additionally, the drilling location is in an area with heavier snowfall, so the ice core layers are better separated.

The above photo shows back-lit ice layers and is from an expanded link in the WSJ article.