Sentences with phrase «volcanic influences»

There is high variability in the solar and volcanic influences on the climate (top row) while greenhouse gas influences rise over time (bottom row).

In fact it is 10 times the underlying (ignoring volcanic influences) predicted rate from the IPCC, which is approximately 0.2 C per decade.

But there are problems with volcanic influences.

If the newer reconstructions are taken into account, then the ratio between solar and volcanic influences increases to 7:1.

Bertrand was investigating the effect of solar and volcanic influence on climate and concluded «these are clearly not sufficient to explain the observed 20th century warming and more specifically the warming trend which started at the beginning of the 1970s».

Figure 2: Derivatives of SOI (dark line) and MSU GTTA (light line) for the period 1981 — 2007 after removing periods of volcanic influence (McLean 2009).

These temperature increases can not be attributed easily to volcanic influences and are most probably solar in origin.»

So find a slice on history with zero volcanic influence, then you have your Volcanic Zero Baseline.

As the graph shows, in addition to aerosol pollution (the sulphate line), volcanic influences were increasingly negative during the period of global cooling, and solar forcing slightly declined.

The Hansen paper is an extreme case, combining a strong volcanic forcing with a model with high sensitivity, and so probably provides an upper bound for the volcanic influence on temperature.

However, as both Lean and Rind (2008) and Foster and Rahmstorf (2011) have shown, once solar and volcanic influences, anthropogenic warming, and ENSO variations are accounted for, there is very little variation left.

Indeed, it is true that the solar and volcanic influences are the most poorly estimated, especially early in the centuryand it is also true that the observations of global average temperature are least well established during this period.

In the case of the SST datasets analysed by Thompson et al. it looks to me that natural variability (volcanic influences, ENSO etc.) have conspired to make a relatively gradual trend look like a sudden one.