Archives de catégorie : climate-debate

Learning from the climate’s history: the Arctic heat waves of the 1930s and 40s

by Dr. Sebastian Lüning and Prof. Fritz Vahrenholt [German text translated/edited by P Gosselin] , April 1, 2017


Now let’s extend the time scale and look back 100 years. What a surprise: In the 1930s and 1940s there were two heat decades in the Arctic which were almost as warm as today (Fig. 2). This is just a small fact that went missing in the WMO press release and in the derwesten.de article.

Global Warming and Hurricanes – NOAA says no measurable effect yet

by Anthony  Watts, April 5, 2017

From NOAA’s Geophysical Fluid Dynamics Laboratory, March  17, 2017


Two frequently asked questions on global warming and hurricanes are the following:

Have humans already caused a detectable increase in Atlantic hurricane activity or global tropical cyclone activity?
What changes in hurricane activity are expected for the late 21st century, given the pronounced global warming scenarios from current IPCC models?

Greenland was nearly ice-free for extended periods during the Pleistocene

by JM Schaefer et al., Nature, December8, 2016


Here we show that Greenland was deglaciated for extended periods during the Pleistocene epoch (from 2.6 million years ago to 11,700 years ago), based on new measurements of cosmic-ray-produced beryllium and aluminium isotopes (10Be and 26Al) in a bedrock core from beneath an ice core near the GIS summit.

On the Existence of a ‘Tropical Hot Spot’

by Dr JP Wallace III et al., August 2016

.pdf (69p.)


These analysis results would appear to leave very, very little doubt but that EPA’s claim of a Tropical Hot Spot (THS), caused by rising atmospheric CO2 levels, simply does not exist in the real world. Also critically important, even on an all-other-things- equal basis, this analysis failed to find that the steadily rising Atmospheric CO2 Concentrations have had a statistically significant impact on any of the 13 critically important temperature time series analyzed.

Methane emissions from trees

Tree trunks act as methane source in upland forests

by University of Delaware, March 30, 2017


Methane is about 25 times stronger than carbon dioxide, with some estimates as high as 33 times stronger due to its effects when it is in the atmosphere.

Because of methane’s global warming potential, identifying the sources and “sinks” or storehouses of this greenhouse gas is critical for measuring and understanding its implications across ecosystems.

Daniel L. Warner, Samuel Villarreal, Kelsey McWilliams, Shreeram Inamdar, Rodrigo Vargas. Carbon Dioxide and Methane Fluxes From Tree Stems, Coarse Woody Debris, and Soils in an Upland Temperate ForestEcosystems, 2017; DOI: 10.1007/s10021-016-0106-8

Absence of 21st century warming on Antarctic Peninsula consistent with natural variability

by J. Turner et al., Nature/July 2016


Here we use a stacked temperature record to show an absence of regional warming since the late 1990s. The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer. Temperatures have decreased as a consequence of a greater frequency of cold, east-to-southeasterly winds, resulting from more cyclonic conditions in the northern Weddell Sea associated with a strengthening mid-latitude jet.

See also : 20+ Scientists: ‘No Continent-Scale Warming Of Antarctic Temperature Is Evident In The Last Century’

Recent Sea-Level Change at Major Cities

by Rich Taylor, March 29, 2017


Where the ground is stable, typical change appears to be a rise of 1- to 2-mm/y. Rates above 3 mm/y seem to have a substantial component of natural and/or anthropogenic subsidence. Rates above 10 mm/y appear to be a primarily a consequence of human activity, which implies they should be manageable to some degree.

All records in this review are from the website www.psmsl.org of the Permanent Service for Mean Sea Level.

Published measurements of climate sensitivity declining

by Laterite, June 20, 2015


The climate sensitivity due to CO2 is expressed as the temperature change in °C associated with a doubling of the concentration of carbon dioxide in Earth’s atmosphere. The equilibrium climate sensitivity (ECS) refers to the equilibrium change in global mean near-surface air temperature that would result from a sustained doubling of the atmospheric carbon dioxide concentration.  The transient climate response (TCR) is defined as the average temperature response over a twenty-year period centered at CO2 doubling in a transient simulation with CO2 increasing at 1% per year. The transient response is lower than the equilibrium sensitivity, due to the “inertia” of ocean heat uptake.

Also, this post

“[T]here is growing evidence of much smaller climate sensitivity to CO2; and even if these drastic emissions reductions occurred, we see little impact on the climate in the 21st century (even if you believe the climate models).”

Alberta’s Proposed Climate Plan: A Burden with No Benefit

by Ken Gregory, July 2005


Energy Balance Climate Sensitivity

The most important parameter in determining the economic impact of climate change is the sensitivity of the climate to greenhouse gas emissions. Climatologist Nicholas Lewis used an energy balance method to calculate the Equilibrium Climate Sensitivity (ECS) best estimate at 1.45 °C. ECS is the global temperature change resulting from a doubling of CO2 in the atmosphere after allowing the oceans to reach temperature equilibrium, which takes about 3000 years in the models.

A more policy-relevant parameter is the Transient Climate Response (TCR) which is the global temperature change at the time of the CO2 doubling. A doubling of CO2 at the current growth rate would take 126 years. The analysis gives the TCR best estimate at 1.21 °C with a likely range [17 – 83% confidence] of 1.05 to 1.45 °C.

The State of the Climate in 2016

by Prof. Dr. Ole Humlum, March 22,  2017


A report on the State of the Climate in 2016 which is based exclusively on observations rather than climate models is published today by the Global Warming Policy Foundation (GWPF).

Contents (37 pages)

1. General overview 2016/2. Spatial pattern of global surface air temperatures in 2016/3. Global monthly lower troposphere air temperatures since 1979/4. Global mean annual lower troposphere air temperatures since 1979 ……………………/17. Ocean temperature net change 2004-2016 in two north-south sectors/18. Pacific Decadal Oscillation…………../23. Global, Arctic and Antarctic sea-ice extent/24. Northern hemisphere snow-cover extent and /25 Links to data sources.

Dead zones may threaten coral reefs worldwide

by Smithsonian Tropical Research Institute, March 21, 2017


Dead zones affect dozens of coral reefs around the world and threaten hundreds more according to a new study. Watching a massive coral reef die-off on the Caribbean coast of Panama, they suspected it was caused by a dead zone — a low-oxygen area that snuffs out marine life — rather than by ocean warming or acidification.

Journal Reference: Andrew H. Altieri, Seamus B. Harrison, Janina Seemann, Rachel Collin, Robert J. Diaz, Nancy Knowlton. Tropical dead zones and mass mortalities on coral reefs. Proceedings of the National Academy of Sciences, 2017; 201621517 DOI: 10.1073/pnas.1621517114

THE LONGEST STRETCH OF A BLANK SUN SINCE 2010

by VENCORE WEATHER, March 20, 2017


Third weakest solar cycle since 1755
A recent publication has analyzed the current solar cycle and has found that when sunspot anomalies are compared to the mean for the number of months after cycle start, there have been only two weaker cycles since observations began in 1755.  Solar cycle 24 began in 2008 after a historically long and deep solar minimum which puts us more than eight years into the current cycle.

The Logarithmic Effect of Carbon Dioxide

by David Archibald, March 8, 2010


The greenhouse gasses keep the Earth 30° C warmer than it would otherwise be without them in the atmosphere, so instead of the average surface temperature being -15° C, it is 15° C. Carbon dioxide contributes 10% of the effect so that is 3° C. The pre-industrial level of carbon dioxide in the atmosphere was 280 ppm. So roughly, if the heating effect was a linear relationship, each 100 ppm contributes 1° C. With the atmospheric concentration rising by 2 ppm annually, it would go up by 100 ppm every 50 years and we would all fry as per the IPCC predictions.

But the relationship isn’t linear, it is logarithmic. In 2006, Willis Eschenbach posted this graph on Climate Audit showing the logarithmic heating effect of carbon dioxide relative to atmospheric concentration

Modern ‘Warmth’ A Brief Excursion From 8,000-Year (Continuing) Cooling Trend

by Kenneth Richard, March 20, 2017


According to an estimate of global sea surface temperature (SST) changes during the last 2,000 years (“Robust global ocean cooling trend for the pre-industrial Common Era“), the addition of the last 2 centuries (1800 to 2000 C.E.) of relatively modest SST warming only changes the overall per-millennium global cooling trend (~0.4°C) by one tenth of one degree.  In other words, using a long-term perspective, the Holocene cooling trend has continued largely uninterrupted during the last two centuries.

Geologic Evidence of Recurring Climate Cycles and Their Implications for the Cause of Global Climate Changes. The Past is the Key to the Future

Don J. Easterbrook, 2011

Department of Geology, Western Washington University, Bellingham, WA 98225, USA


Temperatures have risen approximately a degree or so per century since the coldest part of the Little Ice Age ~500 years ago, but the rise has not been linear. Global temperatures have warmed and cooled many times in 25-35-year cycles, well before the atmospheric CO2 began to rise significantly.

Two episodes of global warming and two episodes of global cooling occurred during the 20th century (Fig. 1). Overall, temperatures during the century rose about the same as the rate of warming per century since the Little Ice Age 500 years ago.

Scrutinizing the carbon cycle and CO2 residence time in the atmosphere

by Hermann Harde, Global and Planetary Change, 24 February 2017


Highlights

An alternative carbon cycle is presented in agreement with the carbon 14 decay.

The CO2 uptake rate scales proportional to the COconcentration.

Temperature dependent natural emission and absorption rates are considered.

The average residence time of CO2 in the atmosphere is found to be 4 years.

Paleoclimatic CO2 variations and the actual CO2 growth rate are well-reproduced.

The anthropogenic fraction of CO2 in the atmosphere is only 4.3%.

Human emissions only contribute 15% to the CO2 increase over the Industrial Era.

Also this link

Baffin Bay and Kane Basin polar bears not ‘declining’ concludes new report

by Polar Bear Science, February 15, 2017


The 2016 Scientific Working Group report on Baffin Bay and Kane Basin polar bears was released online without fanfare last week, confirming what local Inuit have been saying for years: contrary to the assertions of Polar Bear Specialist Group scientists, Baffin Bay and Kane Basin subpopulations have not been declining but are stable.

Climate models for the layman

by Judith Curry, Feb 2017


Professor Judith A. Curry is the author of over 180 scienti c papers on weather and climate and is a recipient of the Henry G. Houghton Research Award from the Amer- ican Meteorological Society in 1992. She recently retired from the Georgia Institute of Technology, where she held the positions of Professor and Chair of the School of Earth and Atmospheric Sciences. She is currently President of Climate Forecast Appli- cations Network.

Atlantique Nord : le risque d’un refroidissement rapide au XXIe siècle revu à la hausse

par D. Swingedouw et al., CNRS, 15 février 2017


Dans le cadre du projet européen EMBRACE, une équipe d’océanographes a réexaminé ces 40 projections climatiques en se focalisant sur un point névralgique au nord-ouest de l’Atlantique Nord : la mer du Labrador. Cette mer est le siège d’un phénomène de convection, qui nourrit à plus grande échelle la circulation océanique de retournement. Ses eaux de surface se refroidissent fortement en hiver, deviennent plus denses que les eaux de profondeur et plongent vers le fond. La chaleur des eaux profondes est transférée vers la surface et empêche la formation de banquise

Current Surface Mass Budget of the Greenland Ice Sheet

Danish Meteorological Institute (DMI), February 2017


Greenland has gained 500 Gt of ice this winter (2016-2017)

Here you can follow the daily surface mass balance on the Greenland Ice Sheet. The snow and ice model from one of DMI’s climate models is driven every six hours with snowfall, sunlight and other parameters from a research weather model for Greenland, Hirlam-Newsnow.