This implies that low solar activity, which is expected by some researchers for the coming decades, cannot considerably slow down global warming caused by humankind’s greenhouse gas emissions.
“The impact of variations in solar activity on the climate is often overestimated,” says Georg Feulner of the Potsdam Institute for Climate Impact Research (PIK). He is the author of the article just published in Geophysical Research Letters. “This is what our new analysis shows for the past – and we can learn from this to understand future climate change.”
Sun spots are a visible sign of solar activity. When their number is small, solar radiation intensity is measurably lower. In the late 17th century, after a slow decrease of solar activity that started around 1600, the sun entered an extended period of rest, the Maunder Minimum. This is often considered to be the dominant cause of the cooling of the Earth’s climate during the Little Ice Age.
Two studies published earlier this year found two very different estimates for solar radiation during the Maunder Minimum. One concludes that radiation intensity at that time was substantially lower than today. The other one says that solar activity was just as low as during the extraordinary solar minimum in the years 2008/09.
The impact of these two estimates of solar radiation on temperatures in the Northern hemisphere during the last 1000 years has now been determined for the first time. Feulner fed the data on solar intensity into a climate model – a computer-based complex system of equations simulating the most important climatic processes in the oceans and the atmosphere. Changes in greenhouse gas concentrations and the cooling effect of sulfate aerosols from volcanic eruptions are also considered. The temperature computed by the model was then compared to temperatures reconstructed from natural climate archives like ice cores, tree rings, sediments and corals.
The result is unequivocal. In the model’s calculations, the estimates from the study concluding that solar radiation in the Little Ice Age was extremely low result in temperatures which are significantly below observed temperatures in periods of low solar activity. The estimates of the other study which did not show big differences between radiation intensity during the Maunder Minimum and the recent solar minimum yield realistic temperatures. So the climatic data from natural archives support the second study. “To understand climate history, we certainly have to take into account all possibly relevant factors,” Feulner says. “However, the impact of solar activity on the climate is comparatively small. That is what the new study confirms.”
Now what do these findings mean for our century in case the sun enters a quiet period comparable to the Maunder minimum as some experts suggest? “This would bring a cooling effect of at most 0.3 degrees,” Feulner says. This could decrease anthropogenic global warming by roughly 10 percent or less. “Regrettably, this is too little to considerably slow down anthropogenic climate change.”
Article: Feulner, G. (2011): Are the most recent estimates for Maunder Minimum solar irradiance in agreement with temperature reconstructions? Geophysical Research Letters, Vol. 38, L16706 [doi:10.1029/2011GL048529]
For further information please contact the PIK press office:Phone: +49 331 288 25 07
Jonas Viering | PIK Potsdam
Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation
Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences