How do sunspots affect the earth

Scanning a huge bank of observations compiled by an international satellite project, they reported that global cloudiness increased slightly at times when the influx of cosmic rays was greater. Later studies and reanalysis of the data found severe errors, and the authors themselves shifted from claiming an effect on high-level clouds to claiming an effect on low-level clouds.

But the study did serve to stimulate new thinking. The proposed mechanism roughly resembled the speculation that Dickinson had offered, with little confidence, back in It began with the fact that in periods of low solar activity, the Sun's shrunken magnetic field failed to divert cosmic rays from the Earth. When the cosmic rays hit the Earth's atmosphere, they not only produced carbon, but also sprays of electrically charged molecules.

Perhaps thiselectrification promoted the condensation of water droplets on aerosol particles? If so, there was indeed a mechanism to produce extra cloudiness. A later study of British weather confirmed that at least regionally there was "a small yet statistically significant effect of cosmic rays on daily cloudiness. Other studies meanwhile revived the old idea that increased ultraviolet radiation in times of higher solar activity might affect climate by altering stratospheric ozone.

While total radiation from the Sun was nearly constant, instruments in rockets and satellites found the energy in the ultraviolet varying by several percent over a sunspot cycle. Plugging these changes into elaborate computer models suggested that even tiny variations could make a difference, by interfering in the teetering feedback cycles that linked stratospheric chemistry and particles with lower-level winds and ocean surfaces.

By the end of the s, many experts thought it was possible that changes in the stratosphere might affect surface weather after all. Meanwhile others speculated about mechanisms through which the powerful electric circuit that circles the planet, and which varies in response to solar activity, might influence cloudiness. While the physics of how solar activity could affect clouds remained obscure, it was now undeniable that possible mechanisms could exist. And while the data were noisy, a growing variety of evidence, some of it going back thousands of years, showed credible correlations between solar activity and one or another feature of the climate.

Whatever the exact form solar influences took, most scientists were coming to accept that the climate system was so unsteady that many kinds of minor external change could trigger a shift. It might not be necessary to invoke exotic cosmic ray mechanisms, for the system might be sensitive even to the tiny variations in the Sun's total output of energy, the solar constant.

The balance of scientific opinion tilted. Many experts now thought there was indeed a solar-climate connection. The Sun vs. When a study reported evidence that the Sun's magnetic field had strengthened greatly since the s, it brought still more attention to the key question: was increased solar activity the main cause of the rise of average global temperature over that period? As the 21st century began, most experts thought it likely that the Sun had driven at least part of the previous century's warming.

Most convincingly, the warming from the s to the s had come when solar activity had definitely been rising, while the carbon dioxide buildup had not yet been large enough to matter much.

A cooling during the s and s followed by the resumption of warming also correlated loosely with changes in solar activity. How far the solar changes had influenced climate, however, remained speculative. The temporary cooling had probably been at least partly related to an increase in smoke from smoggy haze, dust from farmlands, volcanic eruptions, and other aerosols.

It was also possible that the climate system had just swung randomly on its own. One senior solar physicist insisted, "We will have to know a lot more about the Sun and the terrestrial atmosphere before we can understand the nature of the contemporary changes in climate.

By the early 21st century, however, evidence of connections between solar activity and weather was strengthening. Extremely accurate satellite measurements spanning most of the globe revealed a distinct correlation between sea-surface temperatures and the eleven-year solar cycle.

The effect was tiny, not even a tenth of a degree Celsius, but it was undeniable. Similarly weak but clear effects were detected in the atmosphere near the surface and, somewhat stronger, in the thin upper atmosphere. The new findings, however, did pose an important challenge to computer modelers. A climate model could no longer be considered entirely satisfactory unless it could reproduce these faint, but theoretically significant, decade-scale cycles. Rough limits could now be set on the extent of the Sun's influence.

For average sunspot activity decreased after , and on the whole, solar activity had not increased during the half-century since As for cosmic rays, they had been measured since the s and likewise showed no long-term trend. The continuing satellite measurements of the solar constant found it cycling within narrow limits, scarcely one part in a thousand.

Yet the global temperature rise that had resumed in the s was accelerating at a record-breaking pace, chalking up a total of 0. It seemed impossible to explain that using the Sun alone, without invoking greenhouse gases.

For if solar activity had continued to rise, global temperatures might have climbed slightly faster — but scientists would have had a much harder job identifying greenhouse gases as the main cause of the global warming. The most advanced computer modeling groups did manage to reproduce the faint influence of the sunspot cycle on climate. Their calculations showed that since the s that influence had been overtaken by the rising effects of greenhouse gases. The modelers got a good match to maps of the climate changes observed over the past century, but only if they included the effects of the gases, and not if they tried to attribute it all to the Sun.

For example, if they put in only an increase of solar activity, the results showed a warmer stratosphere. Adding in the greenhouse effect made for stratospheric cooling since the gases trapped heat closer to the surface. And cooling was what the observations showed. What about global Sun-climate correlations farther back through time? Paleontologists' studies of isotopes stemming from cosmic rays continued to show a rough connection with the Medieval and Little Ice Age climate anomalies.

And an especially neat study of deposits in a cave in China found a solid correlation between weather and solar activity spanning the past two millennia. However, the correlation had broken down after , just when greenhouse gases began to kick in — evidently overwhelming weaker influences. Painstaking studies simply failed to find any significant correlation between cosmic rays and cloudiness.

The consensus of most scientists, arduously hammered out in a series of international workshops, flatly rejected the argument that the soaring temperatures since the s could be dismissed as a consequence of changes on the Sun.

When Foukal reviewed the question in , he found no decisive evidence that the Sun had played the central role in any climate change, not even the Little Ice Age. The cold spells of the early modern centuries, experts were beginning to realize, could be at least partly explained by other influences. For one, a spate of sky-darkening volcanic eruptions had triggered a period of increased sea ice which reflected sunlight from the North Atlantic region.

In addition, there was evidence that the CO 2 level in the atmosphere had dipped during those centuries possibly because of changes in human populations and agriculture. The greenhouse effect, even then, looked like a main factor in climate change. Still, many experts thought it likely that the Maunder Minimum of solar activity could have had something to do with the early modern climate anomalies, contributing perhaps a couple of tenths of a degree of cooling.

This particularly affected the weather in Europe, the classic location of Little Ice Age cold spells: perhaps low solar activity did make for colder winters there. Whatever the mechanism, a group convened in concluded that solar ultraviolet variations had mainly regional effects and could "contribute very little to global temperature variations.

A few scientists persevered in arguing that much smaller solar changes which they thought they detected in the satellite record had driven the extraordinary warming since the s. But even among these outlying groups, leaders admitted that in the future, "solar forcing could be significant, but not dominant.

It was one example of the indestructible "zombie" theories that plagued discussions. As it happened, solar activity sank to historic lows after Some prominent figures among the opposition to regulating greenhouse gases publicly predicted rapid global cooling.

When temperatures climbed to a new record in and a higher record in , higher still in , etc. By the s the study of "solar-terrestrial relations" as scientists called the topic had settled down to teasing out the numerous complex and subtle ways solar activity might possibly influence specific weather patterns.

Such research required, first, assembling and standardizing vast collections of weather data, and second, adapting one or another of the elaborate supercomputer models of the atmosphere to test hypotheses for complex mechanisms like ozone interactions. The research was pursued vigorously as part of the perpetual enterprise of improving short-term weather predictions, but it was scarcely relevant to climate change. The import of the claim that solar variations influenced climate was now reversed.

Critics had used the claim to oppose regulation of greenhouse gases. But what if the planet really was at least a bit sensitive to almost imperceptible changes in the total radiation arriving from the Sun? The planet would surely react no less strongly to changes in the interference by greenhouse gases with the radiation after it entered the atmosphere.

Some of the scientists who reported evidence of past connections between the Sun and climate changes warned explicitly that their data did not show that the current global warming was natural — it only showed the extreme sensitivity of the climate system to small perturbations. Back in a U. National Academy of Sciences panel had estimated that if solar radiation were to weaken as much as it had during the 17th-century Maunder Minimum, the entire effect would be offset by another two decades of accumulation of greenhouse gases.

A study reported that with the growing rate of emissions, by the late 21st century a Maunder-Minimum solar effect would be offset in a single decade. As one expert explained, the Little Ice Age "was a mere 'blip' compared with expected future climatic change. Total solar irradiance energy received from the Sun as observed directly by satellites The increase in radiation that accompanies a solar flare is a theoretical health hazard to spacewalking astronauts, crew and passengers in high-flying aircraft, but there isn't any evidence that people have actually gotten sick from such exposure.

It's unclear if there's a link between solar weather and changes in the Earth's climate, because our planet's climate is influenced by so many other factors -- from volcanic eruptions to man-made emissions of greenhouse gases. The Maunder minimum in the s and s, when there was almost no sunspot activity, coincided with a period of cold temperatures and severe winters in Europe and North America. However, scientists haven't been able to determine if the two phenomena were actually related, though they think that a decrease in the sun's ultraviolet emissions may have triggered the change in climate.

UFO watchers and paranormal enthusiasts also see links between the unknown and increased sunspot activity, but there may be more of a correlation with the intensity of a person's belief in mystical phenomena. If you have a telescope, you can outfit it with a special solar filter that will protect your eyes from solar radiation and keep it from damaging your telescope as well. You also can project the sun's image onto a white card or paper held a foot or two behind the eyepiece of a telescope or binoculars on a tripod.

Sunspots turned out to be areas of cooler zones on the surface of the sun. These spots are about one-third cooler than the rest of the surface and are protected by magnetic fields that stop the heat from being transmitted into the zone. The magnetic field is formed from underneath the sun's surface, but is able to project itself outside through the surface and all the way to the corona of the sun.

The sun has the largest effect on the climate that we enjoy on Earth. Without it there would be no light, resulting in no growth, since our climate largely relies on the sun to provide the energy needed for photosynthesis. Sunspots were first noticed to affect the Earth when scientists realized that increased activity with sunspots creates increased interference with magnetic instruments on the surface of the earth.

As scientists looked further into this phenomenon, they noticed that near the sunspot, hotter areas of the sun would react with the magnetic field outside the sunspot and create a solar flare. Solar flares project a host of things, including x-rays and energy particles rushing toward the Earth's atmosphere in the form of a geomagnetic storm. The first most noticeable effect of sunspots on our climate were the northern and southern lights, otherwise known as the aurora.

With sunspots come an increase in ultraviolet rays that emit from the outer ring of the sunspots toward Earth. Incidentally, the Sporer, Maunder, and Dalton minima coincide with the colder periods of the Little Ice Age, which lasted from about to More recently it was discovered that the sunspot number during shows a remarkable parallelism with the simultaneous variation in northern hemisphere mean temperatures 2.

There is an even better correlation with the length of the solar cycle, between years of the highest numbers of sunspots.

For example, the temperature anomaly was - 0. Some critics of the theory of man-induced global warming have seized on this discovery to criticize the greenhouse gas theory. All this evokes the important question of how sunspots affect the Earth's climate. To answer this question, we need to know how total solar irradiance received by the Earth is affected by sunspot activity.

Intuitively one may assume the that total solar irradiance would decrease as the number of optically dark sunspots increased. However direct satellite measurements of irradiance have shown just the opposite to be the case. This means that more sunspots deliver more energy to the atmosphere, so that global temperatures should rise.

According to current theory, sunspots occur in pairs as magnetic disturbances in the convective plasma near the Sun's surface. Magnetic field lines emerge from one sunspot and re-enter at the other spot. Also, there are more sunspots during periods of increased magnetic activity.