Sentences with phrase «of global volcanic activity»

Not exact matches

Most of these severe crises are linked to massive volcanic activity, global climate changes and sea level lowstands.

The best global view of the heavily cratered surface of Mercury — a mosaic of more than 140 images snapped by Mariner 10 in March 1974 — reveals expansive plains that may have been created by volcanic activity.

By combining this data with Ridgwell's global climate model, the team deduced the amount of carbon added to the ocean and atmosphere and concluded that volcanic activity during the opening of the North Atlantic was the dominant force behind the PETM.

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.

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.

Researchers have found that glacial erosion and melting ice caps both played a key role in driving the observed global increase in volcanic activity at the end of the last ice age.

Human induced trend has two components, namely (a) greenhouse effect [this includes global and local / regional component] and (b) non-greenhouse effect [local / regional component]-- according to IPCC (a) is more than half of global average temperature anomaly wherein it also includes component of volcanic activities, etc that comes under greenhouse effect; and (b) contribution is less than half — ecological changes component but this is biased positive side by urban - heat - island effect component as the met network are concentrated in urban areas and rural - cold - island effect is biased negative side as the met stations are sparsely distributed though rural area is more than double to urban area.

It's pertinent to your point that the global temperature drifted downwards a tad between 1880ish and 1910ish, a result most likely of the large volcanic activity in that period.

I particularly enjoyed the slides that, when combined (1) provided an overview of hotter and cooler CO2 molecules as it relates to how they are seen from outer space and from profile — because this will make it easier for me to explain this process to others; (2) walked through the volcanic and solar activity vs assigning importance to CO2 changes — because this another way to help make it clearer, too, but in another way; (3) discussed CO2 induced warming and ocean rise vs different choices we might make — because this helps point out why every day's delay matters; and (4) showed Figure 1 from William Nordhaus» «Strategies for Control of Carbon Dioxide» and then super-imposed upon that the global mean temperature in colors showing pre-paper and post-paper periods — because this helps to show just how far back it was possible to make reasoned projections without the aid of a more nuanced and modern understanding.

Thus, Victor the Troll, to contradict all that you wrote @ 221, «the dissipation of aerosols from any given eruption IS caused by a lack of volcanic activity,» and global temperatures CAN «rise above (the) level» «they would have been had the volcanoes not occurred» because the impact of previous volcanism would have also dissipated in the interval.

Reminds me of the UK met Office annual predictions, which forecast annual global temperatures based on atlantic multidecadal oscillation, ENSO, solar, recent volcanic activity and, crucially, radiative forcing due to GHG.

We do have reasonably good estimates of global temperature in the period prior to and after 1910 (or if you prefer 1912, when Novarupta erupted), and we do have reasonably good estimates of volcanic activity during that period and beyond, as illustrated in the paper Kevin cited, by Robock.

You provide no evidence of some substantial increase in volcanic and / or earthquake activity in the global warming period since 1900, or the more recent global warming period of since 1970.

A statistical model (based on the work of Judith Lean at the Naval Research Laboratory) that accounts for solar variability, El Niño, volcanic activity, and greenhouse warming indicates that the underlying trend of global warming has accelerated over the past 15 years.

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.

A paper published in Environmental Research Letters by Rahmstorf, Foster, and Cazenave (2012) applied the methodology of Foster and Rahmstorf (2011), using the statistical technique of multiple regression to filter out the influences of the El Niño Southern Oscillation (ENSO) and solar and volcanic activity from the global surface temperature data to evaluate the underlying long - term primarily human - caused trend.

I'm not predicting huge volcanic eruptions, just cooling, affected mostly by already weak and declining solar activity and continuation of the oscillatory behaviour of the global temperature indices.

Also volcanic activity is being blamed for the lack of global temperature rise yet it is not accepted as part of the reason for the cold a century ago.

If periods of horrific volcanic activity and horrendous meteor strikes barely budged global temperature from its cyclic course of transitions between Ice Ages and Warm Periods, man's puny efforts are surely lost in the noise.

Other leading theories to causes of mass extinctions include: global climate change, changes in sea level, chemical poisoning of the atmosphere and / or oceans, variation in solar radiation, and extreme volcanic activity.

Now imagine the kind of extra volcanic activity that could result from 1, 6, or 250 feet of global sea level rise under the raging rate of human - caused warming and you begin to understand the concern.

The world's climate is way too complex... with way too many significant global and regional variables (e.g., solar, volcanic and geologic activity, variations in the strength and path of the jet stream and major ocean currents, the seasons created by the tilt of the earth, and the concentration of water vapor in the atmosphere, which by the way is many times more effective at holding heat near the surface of the earth than is carbon dioxide, a non-toxic, trace gas that all plant life must have to survive, and that produce the oxygen that WE need to survive) to consider for any so - called climate model to generate a reliable and reproducible predictive model.

10 Most past changes in world climates were caused by natural factors Volcanic activity Motion of the continents Recently scientists have observed climate changes that are the result of HUMAN ACTIVITIES GLOBAL WARMING

This is currently the leading cause of global climate change even though there is always natural factors as well such as volcanic processes and solar activity, but not at the rate of climate change we have seen the last century.

I have heard it said that periods of severe volcanic activity in the geological past increased global temperatures by emitting substantial volumes of greenhouse gases.

A paper published in Environmental Research Letters by Rahmstorf, Foster, and Cazenave (2012) applied the methodology of Foster and Rahmstorf (2011), using the statistical technique of multiple regression to filter out the influences of the El Niño Southern Oscillation (ENSO) and solar and volcanic activity from the global surface temperature data to evaluate the underlying long - term human - caused trend.

Figure 1: Contributions of solar activity (dark blue), volcanic activity (red), ENSO (green), and anthropogenic effects (purple) to global surface warming (HadCRUT observations shown in light blue), according to Lean and Rind (2008).

The climate has changed many times in the geologic past due to natural causes — including volcanic activity, changes in the sun's intensity, fluctuations in Earth's orbit, and other factors — but none of these can account for the current rise in global temperatures.

RFC12 takes a very clever approach to address this issue, applying the methodology of Foster and Rahmstorf (2011), using the statistical technique of multiple regression to filter out the influences of ENSO and solar and volcanic activity from the global surface temperature data (Figure 1).

So solar, volcanic activity, ENSO / AMO etc. are independent of TCR and any measurement of TCR would presumably have accounted for their (presumed estimated) effect upon global temperatures.

Figure 1: Global surface and lower atmosphere temperature data from 5 data sets (with a 12 - month running average) before and after applying the statistical methodology of Foster and Rahmstorf (2011) to remove the influences of ENSO and solar and volcanic activity.

According to climatologist Cliff Harris, we «are seeing an increase in volcanic activity worldwide» and this could easily lead to a period of significant global cooling if it continues...

Precession / obliquity — Precession very favorable while obliquity is lessening and becoming more favorable as compared to the Holocene Optimum period of time and this is why I think the global temperatures in general have been on a decline overall since the Holocene optimum however with fits and starts due to solar activity changes / volcanic activity and enso superimposed upon this general trend.

The images show that the axial valley at 4,000 m water depth is blanketed by an extensive set of pyroclastic deposits, raising important questions regarding the accumulation and discharge of magmatic volatiles on such ridges and demonstrating that large - scale pyroclastic activity is possible along even the deepest portions of the global mid-ocean ridge volcanic system.

http://www.agci.org/docs/lean.pdf «Global (and regional) surface temperature fluctuations in the past 120 years reflect, as in the space era, a combination of solar, volcanic, ENSO, and anthropogenic influences, with relative contributions shown in Figure 6.22 The adopted solar brightness changes in this scenario are based on a solar surface flux transport model; although long - term changes are «50 % larger than the 11 - year irradiance cycle, they are significantly smaller than the original estimates based on variations in Sun - like stars and geomagnetic activity.

Its main message — largely missing from news reports and blogs alike — is that carbon emissions interact with a wide range of other factors, from volcanic activity to El Niño weather patterns, in determining the trajectory of global temperatures.

The unrelated, noncyclical events that reduce hurricane activity, including volcanic eruptions, have masked a progressive rise in sea temperatures because of global warming, he said.

Foster and Rahmstorf (2011) used multiple linear regression to filter out the effects of the El Niño Southern Oscillation (ENSO), and solar and volcanic activity (Figure 2), and found that the underlying global surface and lower atmosphere warming trends have remained very steady in recent years (Figure 3).

In the study (Kathleen Compton, Richard A. Bennett, and Sigrun Hreinsdottir, «Climate driven vertical acceleration of Icelandic crust measured by CGPS geodesy,» Geophysical Research Letters 42 (3): 743 — 750, 2015) the authors don't try to blame «global warming» for increased volcanic activity.

One major volcanic eruption would affect global climate more than any variance in solar activity, and much more than any supposed «man - made climate change» with drastic amounts of particulate matter being expelled into the atmosphere that utterly dwarf the impact of all of us.

1816 is widely referred to as «The Year Without a Summer» because volcanic activity the year before triggered such a significant decrease in global temperatures that many areas of the world had frost and snow throughout their spring and summer seasons.