How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

A Late Holocene Fire History of East-Central Alberta, Canada
Campbell, I.D. and Campbell, C. 2000. Late Holocene vegetation and fire history at the southern boreal forest margin in Alberta, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 164: 279-296.

The authors write that "warmer and drier climate is often assumed to translate into increased fire activity," as has been suggested most recently to be almost universally true by Al Gore in his book An Inconvenient Truth. However, they note that this assumption has been found "to be flawed in situations where the warmer and drier climate leads to a less fire-prone vegetation, such as replacement of conifers with Populus," and they go on to provide an example of this phenomenon.

What was done
Campbell and Campbell analyzed pollen and charcoal records obtained from sediment cores retrieved from three small ponds -- South Pond (AD 1655-1993), Birch Island Pond (AD 1499-1993) and Pen 5 Pond (400 BC-AD 1993) -- located within Canada's Elk Island National Park, which covers close to 200 km2 of the Beaver Hills region of east-central Alberta.

What was learned
"Counter to the intuitive increase in fire activity with warmer and drier climate," which is continually hyped by climate alarmists to be a major consequence of CO2-induced global warming, the Canadian researchers report that "declining groundwater levels during the Medieval Warm Period [MWP] allowed the replacement of substantial areas of shrub birch with the less fire-prone aspen, causing a decline in fire frequency and/or severity, while increasing carbon storage on the landscape," as implied by their Pen 5 Pond data. And they conclude that this scenario "is likely playing out again today," as all three of the sites they studied "show historic increases in Populus pollen and declines in charcoal."

What it means
In discussing their results, Campbell and Campbell note that the earth's present climate "is warmer and drier than that of either the Little Ice Age (which followed the MWP) or the early Neoglacial (preceding the MWP)," and they say we must therefore "consider the present pond levels to be more representative of the MWP than of the time before or after." And since their Pen 5 Pond data indicate that sediment charcoal concentrations have not yet dropped to the level characteristic of the MWP -- even with what they describe as the help of "active fire suppression in the park combined with what may be thought of as unintentional fire suppression due to agricultural activity around the park" -- it would appear that their study sites and their surroundings have not yet attained the level of warmth and dryness they experienced during the MWP, which they describe as having occurred over the period AD 800-1200.

Reviewed 26 November 2008