More peer-reviewed papers soil Michael Mann’s claims: Climate Was Warmer 1000 and 2000 Years Ago

Reprinted from CCNET:

CCNet – 18 October 2012
The Climate Policy Network

Climate Was Warmer 1000 and 2000 Years Ago

This impressive piece of research makes a significant contribution to a growing body of evidence that both the global extent of the Medieval Warm Period, and the temperature was similar, or even greater than the Current Warm Period, even though the atmospheric CO2 concentrations today are some 40% greater than they were during the MWP. –David Whitehouse, The Global Warming Policy Foundation, 17 October 2012

Now another paper, by Esper et al published in the Journal of Global and Planetary Change, shows that not only was the summers of the Medieval Warm Period equal or greater than our current warmth, but that the summers of the Roman Warm Period of 2000 years ago was significantly warmer than today. –Anthony Watts, Watts Up With That, 18 October 2012

We here present a 2000-year summer temperature reconstruction from northern Scandinavia and compare this timeseries with existing proxy records to assess the range of reconstructed temperatures at a regional scale. The new reconstruction is based on 578 maximum latewood density profiles from living and sub-fossil Pinus sylvestris samples from northern Sweden and Finland. The record provides evidence for substantial warmth during Roman and Medieval times, larger in extent and longer in duration than 20th century warmth. –Jan Esper et al, Global and Planetary Change 88–89 (2012) 1–9

Ice sheets retreating due to global warming often suddenly stabilise for “decades to centuries” no matter that the warming is still going on, scientists have found. It would seem that current predictions of sea level rises to be expected on a given timescale with a given amount of global warming will need to be revised – downwards. As the most up-to-date predictions are not very alarming anyway, it could be that sea level rises just aren’t that big a worry, over say the next century anyway. –Lewis Page, The Register, 18 October 2012

An eminent scientist has criticised the leader of Cambridgeshire County Council for denying man’s role in global warming. However Cllr Clarke has won support from members of his party – who loudly cheered as he defended his position at the authority’s latest meeting. His blog posting on the subject drew on Met Office figures which showed there had been no discernible rise in global temperatures in the last 16 years. Pinned down at …

Prof. Judith Curry on 16 year global temps: ‘ Nothing in Met Office’s statement…effectively refutes Rose’s argument that there has been no increase in global avg. surface temps for past 16 years’

Excerpt from Judith Curry:

JC note to defenders of the idea that the planet has been warming for the past 16 years:

Raise the level of your game. Nothing in the Met Office’s statement or in Nuticelli’s argument effectively refutes Rose’s argument that there has been no increase in the global average surface temperature for the past 16 years.

Use this as an opportunity to communicate honestly with the public about what we know and what we don’t know about climate change. Take a lesson from these other scientists that acknowledge the ‘pause’, mentioned in my previous post Candid comments from global warming scientists

Kevin Trenberth:

The hiatus [in warming] was not unexpected. Variability in the climate can suppress rising temperatures temporarily, though before this decade scientists were uncertain how long such pauses could last. In any case, one decade is not long enough to say anything about human effects on climate; as one forthcoming paper lays out, 17 years is required

Trenberth questions whether the Argo measurements are mature enough to tell as definite a story as Hansen lays out. He has seen many discrepancies among analyses of the data, and there are still “issues of missing and erroneous data and calibration,” he said. The Argo floats are valuable, he added, but “they’re not there yet.”

Susan Solomon:

What’s really been exciting to me about this last 10-year period is that it has made people think about decadal variability much more carefully than they probably have before,” said Susan Solomon, an atmospheric chemist and former lead author of the United Nations’ climate change report, during a recent visit to MIT. “And that’s all good. There is no silver bullet. In this case, it’s four pieces or five pieces of silver buckshot.”

Jim Hansen:

These revelations are prompting the science’s biggest names to change their views.

Indeed, the most important outcome from the energy hunt may be that researchers are chronically underestimating air pollution’s reflective effect.

“Less efficient mixing, other things being equal, would mean that there is less warming ‘in the pipeline,’” Hansen said. “But it also implies that the negative aerosol forcing is probably larger than most models assumed. So the Faustian aerosol bargain is probably more of a problem than had been assumed.”

Judith Lean:

Climate models failed to reflect the sun’s cyclical influence on the climate and “that has led to a sense that the