Sun's energy influences 1,000 years of natural climate variability in North Atlantic

Mar 09, 2014
Sun's energy influences 1,000 years of natural climate variability in North Atlantic
This is a composite created from three images received from MODIS instruments carried on NASA's Terra and Aqua polar orbiting satellites. The images were received at the Dundee Satellite Receiving Station at 1151, 1205 and 1342 UTC on 7th Jan. 2010. Credit: NASA

Changes in the sun's energy output may have led to marked natural climate change in Europe over the last 1000 years, according to researchers at Cardiff University.

Scientists studied seafloor sediments to determine how the temperature of the North Atlantic and its localised atmospheric circulation had altered. Warm surface waters flowing across the North Atlantic, an extension of the Gulf Stream, and warm westerly winds are responsible for the relatively mild of Europe, especially in winter. Slight changes in the transport of heat associated with these systems can led to regional climate variability, and the study findings matched historic accounts of , including the notoriously severe winters of the 16th and 18th centuries which pre-date global industrialisation.

The study found that changes in the Sun's activity can have a considerable impact on the -atmospheric dynamics in the North Atlantic, with potential effects on regional climate.

Predictions suggest a prolonged period of low sun activity over the next few decades, but any associated natural temperature changes will be much smaller than those created by human carbon dioxide emissions, say researchers.

The study, led by Cardiff University scientists, in collaboration with colleagues at the University of Bern, is published today in the journal Nature Geoscience.

Dr Paola Moffa-Sanchez, lead author from Cardiff University School of Earth and Ocean Sciences, explained: "We used seafloor sediments taken from south of Iceland to study changes in the warm surface ocean current. This was done by analysing the chemical composition of fossilised microorganisms that had once lived in the surface of the ocean. These measurements were then used to reconstruct the seawater temperature and the salinity of this key ocean current over the past 1000 years."

The results of these analyses revealed large and abrupt temperature and salinity changes in the north-flowing warm current on time-scales of several decades to centuries. Cold ocean conditions were found to match periods of low solar energy output, corresponding to intervals of low sunspot activity observed on the surface of the sun. Using a physics-based climate model, the authors were able to test the response of the ocean to changes in the solar output and found similar results to the data.

"By using the climate model it was also possible to explore how the changes in solar output affected the surface circulation of the Atlantic Ocean," said Prof Ian Hall, a co-author of the study. "The circulation of the surface of the Atlantic Ocean is typically tightly linked to changes in the wind patterns. Analysis of the atmosphere component in the climate model revealed that during periods of solar minima there was a high-pressure system located west of the British Isles. This feature is often referred to as atmospheric blocking, and it is called this because it blocks the warm westerly winds diverting them and allowing cold Arctic air to flow south bringing harsh winters to Europe, such as those recently experienced in 2010 and 2013."

Meteorological studies have previously found similar effects of solar variability on the strength and duration of atmospheric winter blockings over the last 50 years, and although the exact nature of this relationship is not yet clear, it is thought to be due to complex processes happening in the upper layers of the atmosphere known as the stratosphere.

Dr Paola Moffa-Sanchez added: "In this study we show that this relationship is also at play on longer time-scales and the large ocean changes, recorded in the microfossils, may have helped sustain this atmospheric pattern. Indeed we propose that this combined ocean-atmospheric response to solar output minima may help explain the notoriously severe winters experienced across Europe between the 16th and 18th centuries, so vividly depicted in many paintings, including those of the famous London Frost Fairs on the River Thames, but also leading to extensive crop failures and famine as corroborated in the record of wheat prices during these periods."

The study concludes that although the temperature changes expected from future solar activity are much smaller than the warming from human , regional climate variability associated with the effects of on the ocean and atmosphere should be taken into account when making future climate projections.

Explore further: Unstable Atlantic deep ocean circulation under future climate conditions

More information: Solar forcing of North Atlantic surface temperature and salinity over the past millennium, Nature Geoscience, DOI: 10.1038/ngeo2094

add to favorites email to friend print save as pdf

Related Stories

Global warming felt to deepest reaches of ocean

Mar 02, 2014

In the mid-1970s, the first available satellite images of Antarctica during the polar winter revealed a huge ice-free region within the ice pack of the Weddell Sea. This ice-free region, or polynya, stayed ...

Circulation changes in a warmer ocean

Feb 22, 2013

Circulation changes in a warmer ocean In a new study, scientists suggest that the pattern of ocean circulation was radically altered in the past when climates were warmer.

Recommended for you

NASA image: Fires in the southern United States

23 hours ago

In this image taken by the Aqua satellite of the southern United States actively burning areas as detected by MODIS's thermal bands are outlined in red. Each red hot spot is an area where the thermal detectors ...

User comments : 16

Adjust slider to filter visible comments by rank

Display comments: newest first

climate
2.3 / 5 (6) Mar 09, 2014
Reasons and solutions climate change
cantdrive85
1.8 / 5 (21) Mar 09, 2014
The study found that changes in the Sun's activity can have a considerable impact on the ocean-atmospheric dynamics in the North Atlantic, with potential effects on regional climate.

Now solar activity can effect "regional climate". Such a notion to expect it to effect the global climate is too much to consider for some reason.
Jim4321
3.1 / 5 (7) Mar 09, 2014
Quite interesting. What is the mechanism by which the sun influences the blocking highs? If we understand that, then we can begin to unravel how the sun affects climate more generally.
Grallen
3.9 / 5 (11) Mar 09, 2014
@Cantdrive: This is about a 1000 year cycle. Not anything near as fast as what you normally argue(incorrectly) about. Save your energy for relevant comment threads.
dogbert
1.8 / 5 (12) Mar 09, 2014
The study concludes that although the temperature changes expected from future solar activity are much smaller than the warming from human carbon dioxide emissions, regional climate variability associated with the effects of solar output on the ocean and atmosphere should be taken into account when making future climate projections.


So the projections we have been using are not including solar variation and they should?
But we have predetermined that solar variation is going to have a smaller effect than CO2?

The scientific method is strangely lacking in climate "science".
Benni
2.4 / 5 (10) Mar 09, 2014
The last time I left a post in this section, I pointed out that in our astronomy club we had been collating many years of changes in the Martian polar cap with changes in Earth's polar caps. We found those changes to be remarkably similar.............but wouldn't you know that some looney came right in below my post & told me "it isn't the sun" (causing the change). I think his handle name begins with an "r", look out for him, he'll probably be back.
Eddy Courant
1.6 / 5 (7) Mar 09, 2014
Sun Sun Sun here it comes! I can't believe the Sun affects climate. How?
PinkElephant
4.1 / 5 (9) Mar 10, 2014
@dogbert,
So the projections we have been using are not including solar variation and they should?
Note that they are talking about *regional* climate projections, and the chief effect of accounting for solar variation on those scales, is to broaden the error bounds on *some* of the regional projections, where the regional climate is particularly sensitive to solar variation (such as the North Atlantic.)
But we have predetermined that solar variation is going to have a smaller effect than CO2?

After all, we have no way of *forecasting* what the Sun will do over the next several decades and centuries. It might get slightly cooler, or slightly warmer, or stay about the same, or oscillate cyclically. But we *are* able to forecast the effects of CO2. And we do know the rough range of variation in solar output over the last few millennia -- so we might reasonably expect the same range in the near future. The relative effect magnitude estimate is based on such information.
FrankTrades
1.9 / 5 (9) Mar 10, 2014
This is an old theory from the 1960s -- not that it does not hold water -- It was first proposed as a means to explain sedimentation rates through geologic time. I know this for a fact: where I sit in Boston, MA there was 5,000 feet of ice cover only just 12,000 years ago. It sure must have warmed up an awful lot since them without any help from man. And why should the last 1,000 years (or the last 100) be any different?
PinkElephant
4.5 / 5 (8) Mar 10, 2014
@Benni,

You might want to review the following, both individually and with your astronomy club:

"Sun & climate: moving in opposite directions":
http://skepticals...ming.htm

"What climate change is happening to other planets in the solar system":
http://skepticals...stem.htm

(Feel free to read through the "Basic", "Intermediate", or "Advanced" tabs, where available, according to your ability and/or need ;P)
nikola_milovic_378
1.4 / 5 (10) Mar 10, 2014
All past observations and measurements of some phenomenon in the sun and our planet, are only indicators of some deeper and more fundamental developments and laws that govern the relations between the participants in the solar system. Climate change is not the result of human activity on Earth. Such claims are due to self-interest of individuals and systems to help themselves obtain as much benefit from any new use of energy and their resources. Good indicators that something is happening and that is the cause of all these changes, are sunspots and their cycles. Only science and many institutes, as well as NASA, are not interested in hearing and dedicate themselves to what is claimed as new to science. This all previous leads to any true cause of climate change. These causes are obvious, but science does not see them, but there are men who will soon prove, only problem is, that those who know do not have the physical abilities to achieve, and the science that interferes.
runrig
4.4 / 5 (7) Mar 10, 2014
The study found that changes in the Sun's activity can have a considerable impact on the ocean-atmospheric dynamics in the North Atlantic, with potential effects on regional climate.

Now solar activity can effect "regional climate". Such a notion to expect it to effect the global climate is too much to consider for some reason.


One day (not holding breath) Cant you'll twig the idea that Solar variation on the scales observed merely ALTERS atmospheric circulation LOCALLY. And does not significantly alter Global temps (~0.1%). The regional changes are significant but the global averages are not.

It really is quite simple and intuitive... to those with a critical and scientific mind as opposed to holding an ideological viewpoint that is entirely divorced form such necessities.
runrig
4.4 / 5 (7) Mar 10, 2014
Quite interesting. What is the mechanism by which the sun influences the blocking highs? If we understand that, then we can begin to unravel how the sun affects climate more generally.


Weak solar allows CR to impinge on the Stratosphere (high solar blocks them). In the NH winter, as it is facing away from the Sun, then CR can impinge from, well, as the name implies, ... cosmic directions. This destroys O3, causes Stratospheric warming and encourages a -ve AO ( HP in the Arctic) which causes divergence and spillage of cold air to more southern parts than is usual. Europe is most prone as a target for this.
runrig
4.5 / 5 (8) Mar 10, 2014
This is an old theory from the 1960s -- not that it does not hold water -- It was first proposed as a means to explain sedimentation rates through geologic time. I know this for a fact: where I sit in Boston, MA there was 5,000 feet of ice cover only just 12,000 years ago. It sure must have warmed up an awful lot since them without any help from man. And why should the last 1,000 years (or the last 100) be any different?


Ever heard of Milankovitch cycles my friend?
Try Googling and dispel some of your spectacular ignorance.

Benni
1.8 / 5 (10) Mar 10, 2014
The study found that changes in the Sun's activity can have a considerable impact on the ocean-atmospheric dynamics in the North Atlantic, with potential effects on regional climate.

Now solar activity can effect "regional climate". Such a notion to expect it to effect the global climate is too much to consider for some reason.


One day (not holding breath) Cant you'll twig the idea that Solar variation on the scales observed merely ALTERS atmospheric circulation LOCALLY. And does not significantly alter Global temps (~0.1%). The regional changes are significant but the global averages are not.

It really is quite simple and intuitive... to those with a critical and scientific mind as opposed to holding an ideological viewpoint that is entirely divorced form such necessities.


It's the "r" guy he's back, just as I predicted he'd be. Yep, he's still saying it........
runrig
4.4 / 5 (7) Mar 11, 2014
.but wouldn't you know that some looney came right in below my post & told me "it isn't the sun" (causing the change). I think his handle name begins with an "r", look out for him, he'll probably be back.


Only reserved for especial idiots these days my friend.

An interesting reversal of logic, seeing as I'm the expert here on weather/climate... but then I know you guys reserve most contempt for those with knowledge.
What is it you say? - An appeal to authority. Right that would be the same as learning from teachers/lectures at school/university. Give me strength.