Let’s talk about Global Cooling

The evidence is pretty clear that the globe is cooling on most time scales, and right now we are at one of the coolest points in the history of the earth. Looking first at the last 65 million years, since T-Rex was running around:

65_myr_climate_change_rev
Global Temperature estimates over the last 65 million years based on oxygen isotope thermometry of deep-ocean sediment cores from many parts of the world. Data from Zachos et al (2001). Graph by Robert A. Rohde. READ MORE…

The Medieval Warm Period in Antarctica: How two one-data-point studies missed the target

Watts Up With That?

Guest essay by Sebastian Lüning

A common claim by warmists in the climate debate is the alleged absence of the Medieval Warm Period (MWP) in the Southern Hemisphere. In a previous post we discussed the MWP in Australia, New Zealand and Oceania. In the following, we will take a look at Antarctica.

In 2012 a group led by Robert Mulvaney of the British Antarctic Survey published in Nature an ice-core record of deuterium variations from James Ross Island, off the northeastern tip of the Antarctic Peninsula, in which deuterium was used as a temperature proxy. Whilst they found indeed a slight warming centred around 1000 AD, later developments are puzzling. Unexpectedly, the highest temperatures of the past millennium occurred during the Little Ice Age (LIA) around 1750 AD (Fig. 1). And the coldest temperatures were found at 1400 AD, during the late MWP. Based on this apparent mismatch with the…

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Violating the norms and ethos of science

Judith Curry gives a brilliant and thorough critique of a recent paper…

Climate Etc.

by Judith Curry

Don’t let transparency damage science.  – Stephan Lewandowsky & Dorothy Bishop

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