The sun's role in climate change
Description
It is clear that the climate is changing, but the climate has never been stable. Is the current climate change man-made, or has the temperature risen because of increased solar activity?
The remains of plants and other organisms in peat deposits, lake sediments and marine deposits are an important source of information about natural climate changes in the past.
Climate changes during the last 11,000 years often accompanied changing solar activity. Reconstructions of water levels in lakes in France and Switzerland show large changes due to changes in precipitation and temperature. Variations in solar activity determined these climate changes.
The classic transition from the relatively dry and warm Subboreal to the cool, humid Subatlantic around 850 calendar years BC appears to have been caused by a temporary decline in solar activity. The effects of that climate change for Late Bronze Age farmers in the Netherlands and its connection with the sudden expansion of the Scythians in arid southern Siberia will be discussed.
The climate's hypersensitivity to relatively small changes in solar activity indicates the existence of amplification mechanisms in the atmosphere. The lack of knowledge about such mechanisms makes proper modelling of current and future climate impossible. The role of the sun - in relation to the effects of greenhouse gases - is almost certainly greatly underestimated.
Is human actvity a cause of climate change?
There are, however, other reasons to reduce the use of fossil fuels and switch to sustainable forms of energy supply: air quality must improve; further ocean acidification must be stopped; we should preferably not be dependent on unreliable countries; and it is better to use oil to make products from it than to burn it.
18:15 Arrival and introduction
19:00 Dinner
20:15 Presentation and questions
21:30 Housekeeping and drinks
22:00 Closing
Speaker(s)
Dr Bas van Geel, working at the University of Amsterdam
Location
Organiser
Circle Alkmaar
Name and contact details for information
Jaap van Eenennaam