Denne artikkelen viser hvor komplisert det er å finne et mønster i alle de sykler som avgjør solens innflytelse.
Kanskje kan vi ha et varmt klima i enda 2000 år? Basert på Vostok-syklene burde ny istid begynne snart.Impact of the ~ 2400 yr solar cycle on climate and human societies
It is very likely that anthropogenic warming has been overestimated, since solar variability warming is not properly accounted for, according to paleoclimatic data presented here, due to a poor understanding of its mechanisms.
1.According to cosmogenic isotopes, there is a near 2450 year solar variability cycle, named here the Bray cycle for its discoverer.
2. At every low of this cycle for the past 10,300 years there have been significantly long grand solar minima or clusters of grand solar minima, as determined by cosmogenic isotopes.
3. At every low of this cycle for the past 12,800 years there has been a significant period of climate deterioration, generally characterized by global cooling in land and sea, increased iceberg activity, glacier advances, atmospheric changes consistent with equatorward expansion of polar circulation, Hadley cells contraction, and changes in wind and precipitation patterns usually increasing at mid and high latitudes and decreasing at low latitudes with a weakening of the equatorial monsoons.
4. After every low of this cycle for the past 12,800 years there has been a long lasting change in climatic conditions manifested mainly in high latitude changes in vegetation, and reflected in the palynological subdivisions of the Holocene.
5. The lows in this cycle coincide with periods of crisis for human societies while providing also opportunities for adaptation an advancement, and often coincide with important cultural transitions lending support to the hypothesis that climate change acts as an engine for societal progress.
6. Despite a clear and intense paleoclimatic effect, changes in solar activity are not properly accounted for in our current understanding of climate forcings due to our ignorance of the underlying physical mechanisms. This underestimation of solar forcing has the inevitable consequence of an overestimation of anthropogenic forcing.
7. The paleoclimatic effects of very low solar activity lend support to Haigh’s hypothesis of solar induced atmospheric changes due to changes in irradiation and stratospheric ozone.
8. No support for an approaching grand solar minimum comes from the analysis of the ~ 1000-yr Eddy and ~ 2400-yr Bray cycles. Analysis of these two long solar cycles indicates that we are probably in a prolonged warm period likely to last for several more centuries.
9. Analogue analysis suggests an increased probability that the next low in the Bray cycle around 4000 AD could mark the start of the next glacial period.