Sentences with phrase «small net forcing»

Not exact matches

The gradual shift to a strong culture of individualism and self - betterment, the role of technology in driving the transition from boardrooms to basements, the more global and interconnected markets that require greater specialization, flexibility and speed, as well as small - business friendly demographic trends are among those forces that are likely to support a net creation of 150,000 new businesses in Canada in the coming ten years.

[emphasis added] Bast: «We believe that climate has warmed in the second half of the 20th Century, we believe that there is probably a measurable human impact on climate but it's probably very small, we think that natural forces probably overwhelm any impact that human activity can have, that computer models are too unreliable to forecast what the future might hold for climate and finally that a modest amount of warming is probably going to be, on net, beneficial both to human beings and the ecosystem.

A limit of approximately 500 GtC on cumulative fossil fuel emissions, accompanied by a net storage of 100 GtC in the biosphere and soil, could keep global temperature close to the Holocene range, assuming that the net future forcing change from other factors is small.

However, we must (1) compare the solar forcing with the net of other forcings, which enhances the importance of solar change, because the net forcing is smaller than the GHG forcing, and (2) consider forcing changes on longer time scales, which greatly diminishes the importance of solar change, because solar variability is mainly oscillatory.

If there is significant solar heating below the tropopause level then there must be a significant net LW flux up through the tropopause (assuming relatively small convective or kinetic energy transfer through that level), so increasing GHG optical thickness can never saturate the tropopause level forcing at all LW wavelengths (by bringing net LW flux at tropopause to zero) in an equilibrium climate.

The system can have a net negative feedback and still change very much provided a radiative forcing from sunlight or CO2 is sufficiently large, although for typical changes in these variables that Earth encounters, one would indeed expect only relatively small climate changes to occur if negative feedbacks did in fact dominate.

(Note that radiative forcing is not necessarily proportional to reduction in atmospheric transparency, because relatively opaque layers in the lower warmer troposphere (water vapor, and for the fractional area they occupy, low level clouds) can reduce atmospheric transparency a lot on their own while only reducing the net upward LW flux above them by a small amount; colder, higher - level clouds will have a bigger effect on the net upward LW flux above them (per fraction of areal coverage), though they will have a smaller effect on the net upward LW flux below them.

(The planet is never in perfect equilibrium of course, there are small fluctuations in the annual mean that occur in the absence of any forcings, but these fluctuations are small compared to the current anthropogenic forcings and the implied net imbalance).

For a small amount of absorption, the emission upward and downward would be about the same, so if the upward (spectral) flux from below the layer were more than 2 * the (average) blackbody value for the layer temperature (s), the OLR at TOA would be reduced more than the net upward flux at the base of the layer, decreasing CO2 TOA forcing more than CO2 forcing at the base, thus increasing the cooling of the base.

The basis for that view is simply the amount of long wave (LW) energy that is absorbed by the atmosphere is already small which is why forcing is used in place of net heat transfers.

Now, let's take a case such that the aerosols have a big effect, so that the net forcings are much smaller than the median estimate.

Although recent models predict that a small net accumulation of carbon will occur in Arctic tundra during the present century (low confidence), higher methane emissions responding to the thawing of permafrost and an overall increase in wetlands will enhance radiative forcing (medium confidence).

If there are other positive forcings in the system, to get a net forcing of 1.5, it by definition implies that the forcing of CO2 is even smaller than this and even further de bunks the CAGW hypothesis.

And for this the researchers have an explanation — and a funny way of expressing that: the drop from El Niño to La Niña, together with declining solar insulation caused the cooling, because «rapid growth in short - lived sulphur emissions partially offsets rising greenhouse gas concentrations» — thus creating a smaller net anthropogenic climate forcing.

«The overall slow decrease of upwelling SW flux from the mid-1980's until the end of the 1990's and subsequent increase from 2000 onwards appear to caused, primarily, by changes in global cloud cover (although there is a small increase of cloud optical thickness after 2000) and is confirmed by the ERBS measurements... The overall slight rise (relative heating) of global total net flux at TOA between the 1980's and 1990's is confirmed in the tropics by the ERBS measurements and exceeds the estimated climate forcing changes (greenhouse gases and aerosols) for this period.

Net anthropogenic forcing rises 0.13 W / m2 between 2002 and 2007, which is smaller than the 0.24 W / m2 rise between 1997 and 2002.

On net, human activity has a small positive effect on temperature after 1999 because of slight increases in anthropogenic forcing and on - going adjustments to postindustrial increases in anthropogenic forcings (Fig. 3).

Do you honestly think that when a paper / website you quote writes that clouds cause 100 W / m ² LW forcing or -21 W / m ² net forcing that this is the forcing when cloud cover changes by a small percentage?

Re # 5 As far as I understand it (drawing on my recollections of a lecture Hansen gave here at Yale a few weeks back), the actual net forcing associated with Milankovich cycles is relatively small, but it tends to trigger massive feedbacks (e.g. polar ice expanding, lowering albedo, cooling, expanding more) that «snowball» into a glacial period.

Put in a two - hemisphere energy - balance model and using observed hemispheric temperature changes and ocean heat uptake changes you can easily arrive at an independent total aerosol forcing estimate - one that also implies small net total aerosol forcings that are reasonably consistent with the latest observatiional findings.

In all cases, however, the net radiative forcing changes for the non-CO2 gases are small after 2100 and negligible after about 2200.