Sentences with phrase «during volcanic cooling»

Not exact matches

The data showed that, in comparison to today, the Atlantic Ocean surface circulation was much weaker during the Little Ice Age, a cool period thought to be triggered by volcanic activity that lasted from 1450 - 1850.

Like the particles emitted during volcanic eruptions, sulfate aerosols cool the Earth by blocking a portion of the sun's rays.

As discussed elsewhere on this site, modeling studies indicate that the modest cooling of hemispheric or global mean temperatures during the 15th - 19th centuries (relative to the warmer temperatures of the 11th - 14th centuries) appears to have been associated with a combination of lowered solar irradiance and a particularly intense period of explosive volcanic activity.

Further, during volcanic eruptions the ocean cools but for another reason: because volcanic aerosols shade the sun and thus the oceans are heated less than normal.

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.

See e.g. this review paper (Schmidt et al, 2004), where the response of a climate model to estimated past changes in natural forcing due to solar irradiance variations and explosive volcanic eruptions, is shown to match the spatial pattern of reconstructed temperature changes during the «Little Ice Age» (which includes enhanced cooling in certain regions such as Europe).

We now have excellent proxy volcanic data and pretty good ocean heat content proxy data over the past 2000 years, during which their were both warmer and cooler periods.

Even during the PETM, it took extended volcanic eruptions on a massive scale that were extensive but not of the kind to eject significant stratospheric sulfates so as to cause cooling.

Taking the aerosol — or volcanic emanation, it doesn't matter which — as cooling factor, means that CO2 forcing was overestimated during the post 1975, pre-98 period, and overestimated during the post-98 period.

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.

The additional variability implies cooler conditions, predominantly during the 12th to 14th, the 17th and the 19th centuries; these are likely linked to natural forcings due to volcanic eruptions and / or solar activity.

This reveals an ignorance of the literature, otherwise you'd know that the extent of aerosol cooling is estimated from the measured aerosol optical depth due to volcanic eruptions and their consequent impact on global temperature, and estimates of aerosol emissions during the 20th century.

«The solar and volcanic forcings we use are derived from reconstructions based on proxy data and are therefore also subject to considerable uncertainties, although recent explosive volcanic eruptions are likely to have cooled climate, and independent records of solar activity levels inferred from the cosmogenic isotope 10Be (43) and geomagnetic records (44) provide support to reconstructions (22, 45) that show generally increasing solar activity during the 20th century (12).»

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.

Li et al., 2017 (DOI: 10.1016 / j.quascirev.2017.01.009): «Additionally, increased El Nino - Southern Oscillation (ENSO) strength (possibly El Ni ~ no - like phases) during drying periods, increased volcanic eruptions and the resulting aerosol load during cooling periods, as well as high volumes of greenhouse gases such as CO2 and CH4 during the recent warming periods, may also play a role in partly affecting the climatic variability in NC, superimposing on the overall solar dominated long - term control.»

Volcanic eruptions and El Niño events are identified as sharp cooling events punctuating a long - term ocean warming trend, while heating continues during the recent upper - ocean - warming hiatus, but the heat is absorbed in the deeper ocean.

We can plainly see the highs during the 1998 and 2010 el Ninos, and the lows during the 2008 la Nina as well as the volcanic coolings in the early 1980s and early 1990s.

We can see the temperature forcing of El Nino episodes driven by the surface cooling from large stratospheric volcanic events, and some research suggests that near permanent El Nino conditions existed during full glaciation ~ 20kyrs ago.

Earth has experienced extended periods of cooling due to more frequent explosive volcanic eruptions and periods of few sunspots — such as during the «Little Ice Age» which lasted roughly from 1300 to the 1800s.

For example, there are oceanic cycles like the El Niño Southern Oscillation (ENSO, comprised of El Niño and La Niña events), an 11 - year solar cycle, and particulates released during volcanic eruptions which cause short - term cooling by blocking sunlight.

The minimum phase showed higher frequency events of volcanic activity than the maximum phase during the warming period, opposite to the cooling period.

Fine particles created during powerful volcanic eruptions, such as Mount Tambora in 1815, Mount Krakatau in 1883, and Mount Pinatubo in 1991; can spread out high above the ground, forming an invisible, umbrella - like shield that blocks some of the incoming solar radiation and causes temporary global cooling.

«Modelling studies are also in moderately good agreement with observations during the first half of the 20th century when both anthropogenic and natural forcings are considered, although assessments of which forcings are important differ, with some studies finding that solar forcing is more important (Meehl et al., 2004) while other studies find that volcanic forcing (Broccoli et al., 2003) or internal variability (Delworth and Knutson, 2000) could be more important... The mid-century cooling that the model simulates in some regions is also observed, and is caused in the model by regional negative surface forcing from organic and black carbon associated with biomass burning.