Sentences with phrase «volcanic cooling effects»

Because of the too - high sensitivity they also over-predict volcanic cooling effects, but the AR5 assumed forcings minimize that problem by halving volcanic aerosol forcing over previously used (and in the case of Pinatubo, observed) values.

Not exact matches

Besides SSCE, scientists have also been investigating stratospheric sulfur injections — firing sun - reflecting aerosols into the air, similar to the cooling effect after a volcanic eruption — and cirrus cloud thinning, where you thin the top level of clouds, which have a warming effect on the planet.

In this case, researchers are attempting to re-create the effects of volcanic eruptions to artificially cool Earth.

Interestingly, some scientists argue that without the cooling effect of major volcanic eruptions such as El Chichn and Mount Pinatubo, global warming effects caused by human activities would have been far more substantial.

Researchers know that large amounts of aerosols can significantly cool the planet; the effect has been observed after large volcanic eruptions.

But the simulations also reveal that the technique, which mimics the short - term cooling effects of volcanic eruptions, could chill the planet if overdone.

Scientists have long known of the cooling effect of major volcanic eruptions, which spew large amounts of light - scattering aerosols into the stratosphere.

A few years ago, he was trying to get people to take to his idea of how to mitigate global warming by pumping sulfur dioxide into the stratosphere, mirroring the cooling effect caused by large volcanic eruptions.

It's also now well understood that large volcanic eruptions have a short - term cooling effect, see GW FAQ: effect of volcanic activity (short - term being the key phrase, after Church et al Nature 2005, and also http://www.llnl.gov/str/JulAug02/Santer.html)

One just included the effective influence on temperatures from manmade forces (including greenhouse gases and aerosols, which tend to have a cooling effect), while the second included both manmade and natural ones (including volcanic activity and solar radiation).

It is also well known that volcanic activity has a cooling influence, and as is well documented by the effects of the 1991 Mount Pinatubo volcanic eruption.

At a recent conference, scientists explained how a major atmospheric circulation known as the North Atlantic Oscillation (NAO) was in a negative phase at the onset of the LIA, which amplified the cooling effect of a reduction in solar irradiance and volcanic activity.

Over the last 30 years of direct satellite observation of the Earth's climate, many natural influences including orbital variations, solar and volcanic activity, and oceanic conditions like El Nino (ENSO) and the Pacific Decadal Oscillation (PDO) have either had no effect or promoted cooling conditions.

In the troposphere, major volcanic events have a strong cooling effect, as stratospheric aerosols reflect away some incoming solar radiation before it enters the troposphere.

The effects of aerosol injections are at least somewhat known, since volcanic eruptions produce aerosols naturally and have produced cooling in the past.

It is to be noted here that there is no necessary contradiction between forecast expectations of (a) some renewed (or continuation of) slight cooling of world climate for a few decades to come, e.g., from volcanic or solar activity variations; (b) an abrupt warming due to the effect of increasing carbon dioxide, lasting some centuries until fossil fuels are exhausted and a while thereafter; and this followed in turn by (c) a glaciation lasting (like the previous ones) for many thousands of years.»

In other words, if we are after a cause (or causes) for the temperature increase during the period in question, the presence or absence of aerosols from volcanic eruptions is beside the point, because they can not explain any increase in temperatures that occurred prior to any cooling effect they might have had.

What he really means, of course, is that additional volcanic activity, had it taken place, would have added more aerosols, thus slowing the overall dissipation, which would in turn have enhanced the cooling effect of said aerosols.

One of the things I'm having trouble with is the uncertainties of aerosals and their effects on cooling, or the possibility of volcanic eruptions producing particles that result in cooling.

Low volcanic activity (as eruptions can have a cooling effect by blocking out the sun).»

The MM was also a time of enhanced volcanic activity, and the cooling from this was probably comparable with the cooling due to solar effects (an exact attribution is impossible given the uncertainties in both forcings).

In the late 17th Century for instance, our work has suggested about a 50 - 50 split between volcanic and solar effects (compared to the late 18th Century) which enhances the global cooling.

Since aerosols last much longer in the stratosphere than they do in the rainy troposphere, the amount of aerosol - forming substance that would need to be injected into the stratosphere annually is far less than what would be needed to give a similar cooling effect in the troposphere, though so far as the stratospheric aerosol burden goes, it would still be a bit like making the Earth a permanently volcanic planet (think of a Pinatubo or two a year, forever).

Some longer - term effects may remain after several consecutive eruptions, but even then, the 0.1 K cooling by volcanic eruptions over the past 600 years (0.3 K modeled over the past 100 years, see fig. 1 on this page) seems rather high...

Some particles reflect sunlight back to space (aerosols), similar to the volcanic particles, having a cooling effect.

For instance, the warming that began in the early 20th century (1925 - 1944) is consistent with natural variability of the climate system (including a generalized lack of significant volcanic activity, which has a cooling effect), solar forcing, and initial forcing from greenhouse gases.

Combining the effects of volcanic aerosols, plus the negative IPO, it is actually amazing that instead of a mere «hiatus» we haven't seen more severe cooling over the past 15 years.

Volcanic eruptions represent one kind of natural event whose lofting of sulfur dioxide high into the stratosphere can create tiny particles that can have a temporary cooling effect.

Like Foster and Rahmstorf, Lean and Rind (2008) performed a multiple linear regression on the temperature data, and found that although volcanic activity can account for about 10 % of the observed global warming from 1979 to 2005, between 1889 and 2006 volcanic activity had a small net cooling effect on global temperatures.

Volcanic activity was high during this period of history, and we know from modern studies of volcanism that eruptions can have strong cooling effects on the climate for several years after an eruption.

In fact, the major effect of significant volcanic eruptions is cooling due to the sulfate aerosols that they release (although in order to have a significant cooling effect, the eruption has to be large enough that it injects the aerosols into the stratosphere where they can stay around longer... and it apparently helps if the eruption is reasonably near to the equator).

For example, even though the volcanic effect is short - lived it will still have an impact on the water cycle - less evaporation because it's cooler therefore less water vapour, lowering temperature a bit more.

But don't forget the distinction between the cooling effects of volcanic SO2 into the stratosphere versus the warming effects of CO2 into the troposphere.

It takes a couple of years for most of the aerosols from a large volcanic eruption to settle out of the air, so their cooling effect likewise lasts a couple of years.

It could be a relatively cheap, effective and quick way to cool the planet by mimicking the natural effects on climate of large volcanic eruptions, but scientists concede there could be dramatic and dangerous side effects that they don't know about.

In fact, the rate of change of CO2 levels actually drops slightly after a volcanic eruption, possibly due to the cooling effect of aerosols.

In effect, these particles — whether aerosols or kitchen table salt — could act like natural aerosols that cool the planet after a volcanic eruption.

The coming eruption has the potential to create a global cooling effect on Earth's climate called a volcanic winter.

For example, the accumulated effect of volcanic eruptions during the past decade, including the Icelandic volcano with the impossible name, Eyjafjallajökull, may have had a greater cooling effect on the earth's surface than has been accounted for in most climate model simulations.

And thanks for putting me straight on volcanic activity — I was always under the misapprehension that it had a cooling effect.

Aerosols from volcanic eruptions do have a cooling effect once they reach the stratosphere but the effect of high wind speed in the upper atmosphere would rapidly disperse these, and any local effects would be very slight.

If you take into account the two major volcanic eruptions in the beginning of the observed period which had an approximately five year cooling effect each you will find that there has actually been almost no warming since 1980.

This would replicate the cooling effect of large volcanic eruptions, which occasionally belch sulphur dioxide into the stratosphere.

Instead of responding only to the cooler temperatures, the tree rings also included signals from reduced light availability (from the shading effect of volcanic aerosols) and the two effects together produced a signal greater than what would have been produced by cooler temperatures alone.

But not only did Michaels make no mention of Scenarios B & C, he also never mentioned that Hansen's paper included the cooling effect of a major volcanic eruption (in Scenarios B & C) nor did he make any mention that one in fact occurred — Mt. Pinatubo (and neither does O» Donnell, at least the part you quoted).

This means that volcanic aerosols have minimal long - term cooling effects and therefore, the warming effect of CO2 has to be much lower than assumed in Hansen's climate models and thus climate sensitivity estimates must be lowered even further.

New UBC research shows that climate change may impede the cooling effect of volcanic eruptions.

The Sulfate cooling mechanism is also evidenced whenever there is a high ejecta mass volcanic eruption, which causes a measurable cooling effect, for about 3 years after an eruption; until the sulfate particulate aerosols diminish in the atmosphere to the point that they become negligible.

Re my above comment (# 23)-- I should have stated that volcanic forcing predominantly warms the stratosphere, and has little effect — mainly a slight cooling — on the troposphere due to its ability to reduce the intensity of solar radiation reaching the troposphere and the surface.

Backing that up, NASA says that 1) sea surface temperature fluctuations (El Niño - La Niña) can cause global temperature deviation of about 0.2 °C; 2) solar maximums and minimums produce variations of only 0.1 °C, warmer or cooler; 3) aerosols from natural sources such as volcanic eruptions (Mount Pinatubo for example) have caused average cooling of 0.3 °C, but recent eruptions have had not had significant effect.