Sentences with phrase «natural aerosol forcing»

Not exact matches

Taking factors such as sea surface temperature, greenhouse gases and natural aerosol particles into consideration, the researchers determined that changes in the concentration of black carbon could be the primary driving force behind the observed alterations to the hydrological cycle in the region.

The models, which factor in natural effects such as solar winds and volcanic eruptions, along with anthropogenic forcings like greenhouse gases and aerosols, match these precipitation variations accurately in trend and reasonably well in magnitude.

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).

The red line shows the effective temperature forcing of greenhouse gases and aerosols (converted to CO2), and the blue line shows the forcing from both those manmade sources and natural factors, like solar radiation.

The total forcing from the trace greenhouse gases mentioned in Step 3, is currently about 2.5 W / m2, and the net forcing (including cooling impacts of aerosols and natural changes) is 1.6 ± 1.0 W / m2 since the pre-industrial.

The weight of natural factors therefore also is near zero whereas the weight of anthropogenic forcing (GHG minus aerosols) is very high.

Only a few estimates account for uncertainty in forcings other than from aerosols (e.g., Gregory et al., 2002a; Knutti et al., 2002, 2003); some other studies perform some sensitivity testing to assess the effect of forcing uncertainty not accounted for, for example, in natural forcing (e.g., Forest et al., 2006; see Table 9.1 for an overview).

The measured energy imbalance accounts for all natural and human - made climate forcings, including changes of atmospheric aerosols and Earth's surface albedo.

Natural external forcing also results from explosive volcanism that introduces aerosols into the stratosphere (Section 2.7.2), leading to a global negative forcing during the year following the eruption.

Thus to provide the clearest picture of the CO2 effect, we approximate the net future change of human - made non-CO2 forcings as zero and we exclude future changes of natural climate forcings, such as solar irradiance and volcanic aerosols.

In addition, both internal variability and aerosol forcing are likely to affect tropical storms in large part though changes in ocean temperature gradients (thereby changing ITCZ position and vertical shear), while greenhouse gases likely exert their influence by more uniformly changing ocean and tropospheric temperatures, so the physics of the problem may suggest this decomposition as more natural as well.

One type of inverse method uses the ranges of climate change fingerprint scaling factors derived from detection and attribution analyses that attempt to separate the climate response to greenhouse gas forcing from the response to aerosol forcing and often from natural forcing as well (Gregory et al., 2002a; Stott et al., 2006c; see also Section 9.4.1.4).

The use of scrubbers (yes China and India installed scrubbers although not used consistently) to remove SO2 along with the shift to natural gas means the amount of aerosols has not kept up with CO2 forcing.

The total forcing from the trace greenhouse gases mentioned in Step 3, is currently about 2.5 W / m2, and the net forcing (including cooling impacts of aerosols and natural changes) is 1.6 ± 1.0 W / m2 since the pre-industrial.

Also, due to the multiplicity of anthropogenic and natural effects on the climate over this time (i.e. aerosols, land - use change, greenhouse gases, ozone changes, solar, volcanic etc.) it is difficult to accurately define the forcings.

I can't tell how they've accounted for natural removal by the oceans, and they do assume other forcings (such as cooling from aerosols) are removed.

You need information about the degree of intrinsic variability, estimates of the natural forcings (principally solar and volcanic), and estimates of the human related forcings (GHGs, land use change, aerosols etc.).

Summary for Policymakers Chapter 1: Introduction Chapter 2: Observations: Atmosphere and Surface Chapter 3: Observations: Ocean Chapter 4: Observations: Cryosphere Chapter 5: Information from Paleoclimate Archives Chapter 6: Carbon and Other Biogeochemical Cycles Chapter 7: Clouds and Aerosols Chapter 8: Anthropogenic and Natural Radiative Forcing Chapter 8 Supplement Chapter 9: Evaluation of Climate Models Chapter 10: Detection and Attribution of Climate Change: from Global to Regional Chapter 11: Near - term Climate Change: Projections and Predictability Chapter 12: Long - term Climate Change: Projections, Commitments and Irreversibility Chapter 13: Sea Level Change Chapter 14: Climate Phenomena and their Relevance for Future Regional Climate Change Chapter 14 Supplement Technical Summary

Given the total irrelevance of volcanic aerosols during the period in question, the only very modest effect of fossil fuel emissions and the many inconsistencies governing the data pertaining to solar irradiance, it seems clear that climate science has no meaningful explanation for the considerable warming trend we see in the earlier part of the 20th century — and if that's the case, then there is no reason to assume that the warming we see in the latter part of that century could not also be due to either some as yet unknown natural force, or perhaps simply random drift.

They will have a serious impact and will delay advances in understanding carbon dioxide sources and sinks (OCO), natural and man - made aerosols (Glory), and solar climate forcing (Glory).

So the Glory mission was a key part of understanding how both natural (Sun) and human (aerosols) forcings are acting to change our current and future climate.

The weight of natural factors therefore also is near zero whereas the weight of anthropogenic forcing (GHG minus aerosols) is very high.

The NCAR CSM 1.4 was driven by the radiative forcings (volcanic + solar natural and anthropogenic ghg + aerosol) developed in Ammann et al (2007).

ANT = anthropogenic forcing NAT = natural forcing ALL = natural plus anthropogenic CTL = preindustrial control run SUL = sulfate aerosol forcings

Multi-signal detection and attribution analyses, which quantify the contributions of different natural and anthropogenic forcings to observed changes, show that greenhouse gas forcing alone during the past half century would likely have resulted in greater than the observed warming if there had not been an offsetting cooling effect from aerosol and other forcings.

... we strongly support Delworth and Knutson's (2000) contention that this high - latitude warming event represents primarily natural variability within the climate system, rather than being caused primarily by external forcings, whether solar forcing alone (Thejll and Lassen, 2000) or a combination of increasing solar irradiance, increasing anthropogenic trace gases, and decreasing volcanic aerosols.

These warming trends are consistent with the response to increasing greenhouse gases and sulphate aerosols and likely can not be explained by natural internal climate variations or the response to changes in natural external forcing (solar irradiance and volcanoes).

The IPCC has failed to convincingly explain the pause in terms of external radiative forcing from greenhouse gases, aerosols, solar or volcanic forcing; this leaves natural internal variability as the predominant candidate to explain the pause.

Since the true impacts of longer term natural variability are not known and the one confidence estimates of aerosol and cloud forcings used to tune the models to that «range of comfort» are quite a bit more uncertain that previously considered, that it might just be time for a do over.

The early 20th saw a relative balance of anthro forcings, CO2 up and aerosol pollution down, natural (volcanic) aerosols decreased (up) and solar increased (up).

Natural oscillations (mainly solar) and variable non-CO2 forcing like aerosols have caused fluctuations up to + / -0.1 C about that trends so no one expects it to follow the CO2 curve more closely than to within about a tenth of a degree, but the overall rise remains 1 C (+ / -0.1 C) and the overall CO2 forcing of 2 W / m2 is consistent with that.

The only factors under natural forcing was solar irradiance, volcanic aerosols.

Here we apply such a method using near surface air temperature observations over the 1851 — 2010 period, historical simulations of the response to changing greenhouse gases, aerosols and natural forcings, and simulations of future climate change under the Representative Concentration Pathways from the second generation Canadian Earth System Model (CanESM2).

I'm puzzled by your assignment of only a 30 percent probability to the proposition that «Global climate model simulations that include anthropogenic forcing (greenhouse gases and pollution aerosol) provide better agreement with historical observations in the second half of the 20th century than do simulations with only natural forcing (solar and volcanoes).»

Black lines show observed global mean annual mean temperature from HadCRUT3, and thin coloured lines show global mean temperature from five - member ensembles of CanESM2 forced with (a) anthropogenic and natural forcings (ALL), (b) natural forcings only (NAT), (c) greenhouse gases only (GHG), and (d) aerosols only (AER).

Global climate model simulations that include anthropogenic forcing (greenhouse gases and pollution aerosol) provide better agreement with historical observations in the second half of the 20th century than do simulations with only natural forcing (solar and volcanoes).

How would the answer to this change if the pause was either A. an offset of GHG's and aerosols and other anthro cooling forcings, or B. an offset of GHG's by primarily (> 50 %) natural cooling trends?

Primary emphasis is placed on investigation of climate sensitivity — globally and regionally, including the climate system's response to diverse forcings such as solar variability, volcanoes, anthropogenic and natural emissions of greenhouse gases and aerosols, paleo - climate changes, etc..

Causes of natural variability include forcings that are external to the climate system (e.g., volcanic eruptions and aerosols and the 11 - year sunspot cycle) and internal fluctuations (weather phenomena, monsoons, El Niño / La Niña, and decadal cycles).

For the natural forcings Robock made various runs using different solar forcings and two runs using different volcanic aerosol numbers.

They also made choices for aerosols and end dates to suit their desired result, for example considering today's natural forcing to be something like 1940.

The GCMs can be run with any combination of forcings, eg: natural only, anthropogenic only, natural and anthropogenic together, different individual forcings (eg: solar, GHGs, aerosols, land use, volcanoes) separately, or no forcings at all.

Regarding your statement, «Perhaps it is known that the natural variations in surface temperature are all due to unforced mechanisms, otherwise it is simply an assertion», I assume by «natural variations» you mean ENSO, PDO, AMO, etc., because obviously natural changes in solar irradiance or volcanic aerosols are recognized as forcing mechanisms.

a) that natural forcing represented 7 % of the total forcing b) that all anthropogenic forcing componenets other than CO2 (other GHGs, aerosols, land use changes, etc.) cancelled one another out, so that forcing from CO2 = total anthropogenic forcing c) that the CO2 / temperature relation is logarithmic

They explain the pause as warming due to CO2, counteracted by cooling due to aerosols (see e.g. Table, p. 54 of the Technical Summary to AR5) and mysterious unknown forces («natural variability»).

The latter can be considered in terms of forcings and natural unforced variations.The major positive forcings were those from GHGs, black carbon aerosols, and solar irradiance (including its spectral components).

In order to better understand the causes of the Arctic's changing climate, the authors used observational data and nine CMIP5 global climate models to tease apart the effects of anthropogenic greenhouse gas emissions, natural forcings and other anthropogenic forcings (aerosols, ozone and land use changes).

The black line represents five - year mean observed Arctic temperature anomalies, the coloured lines represent the simulated responses to all forcings (red), greenhouse gases alone (green), other anthropogenic forcings alone (mostly aerosols, orange) and natural forcings (blue).

When looking at longer cycles of variability, you have to be careful not to include solar variation and aerosol forcing that are not part of natural variability, and that seem to account for a lot of the long - term effects in the temperature record.

Irrespective of what one thinks about aerosol forcing, it would be hard to argue that the rate of net forcing increase and / or over-all radiative imbalance has actually dropped markedly in recent years, so any change in net heat uptake can only be reasonably attributed to a bit of natural variability or observational uncertainty.