That’s what the self-anointed ‘consensus of scientists’ claims. As noted in a previous post this week, right after the IPCC famously declared that the 1990s were likely the warmest decade of the past millennium, they stated: “Evidence does not support the existence of globally synchronous periods of cooling or warming associated with the ‘Little Ice Age’ and ‘Medieval Warm Period’” (Third Assessment Report, Chap. 2, p. 102).
But those remarkable Idsos, Shirwood, Craig, and Keith, keep reviewing studies that find evidence of the Medieval Warm Period (MWP) and Little Ice Age (LIA) not only in Europe but also in Asia, Africa, Australia/New Zealand, North America, South America, the Oceans, and even Antarctica. What’s more, the preponderance of these studies indicate that the MWP was warmer than the current warm period (CWP). The Idsos divide these studies into two categories, Level 1 Studies, which attempt to quantify the difference between MWP peak temperatures and CWP peak temperatures, and Level 2 Studies, which indicate whether the MWP peak temperatures were higher than, lower than, or the same as CWP peak temperatures.
This week on their Web site, CO2Science.Org, the Idsos review a study, published in Earth and Planetary Science Letters, that attempts to reconstruct the temperature history of the Antarctic Peninsula from ikaite crystals (an icy version of limestone) in marine sediments. The study, by Zunli Lu of Syracuse University and colleagues, finds that “both the Medieval Warm Period and Little Ice Age extended to the Antarctic Peninsula.” What is more, the researchers find that the “climatic signature” from the most recent crystals is “not yet as extreme in nature as the MWP.”
Prof. Lu cautions that the study “does not question the well-established anthropogenic warming trend” of recent decades and that results from one site “should not be extrapolated to make assumptions about climate conditions across the entire globe.” Nonetheless, the Idsos reasonably conclude that the study is additional evidence that “the Earth has not yet eclipsed the level of global warmth experienced during the MWP.”