Geoscience Reference
In-Depth Information
The mid continental latitudes
High summer, in the catchment of the River Gutfluve, at the turn of the 21st
century was close to idyllic. Its place, in the centre of mainland Europe, had
brought the blessings of deep fertile soils, deposited 15,000 years earlier by the
glaciers, still large patches of deciduous forest, a rich local culture, with notable
festivals celebrating beer and music, wine and food. It was the culmination of 5000
years of human settlement that had, of course, removed the native wild forest
ecosystem with its aurochs, bison, bear and wolf, but replaced it with a cultural
landscape that was still interesting, pleasant to look at and equable to live in.
On the hills, a cold winter at −4 °C still led to an average yearly temperature
of 9 °C and summer maxima that could reach 20 °C. There were still mixed forests
of conifers and hardwoods, and a forestry industry that produced timber from
plantations for building and burning. In the lowlands it was generally above
freezing in winter and rose to a sometimes uncomfortable 35 °C in mid summer,
but generally it was around 25 °C. Snow lay for 2 months on the hills but for a
much shorter period in the lowlands, so that crops of wheat, maize, potatoes, and
even some vines, graced the fields and the cattle were fat. Total precipitation of
700 mm gave a well-watered spring, but with 400 mm of evaporation, the late
summer was dry and the crops needed to be irrigated from the river or the
groundwater. Reservoirs had been constructed along the river for storage of
water for drinking. Indeed, the river was mostly engineered in the lowlands and
the flood plain had been lost to agriculture and riverside towns, but at the foot
of the hills was a stretch where a system of traditional flood plain fishponds,
managed with the experience of hundreds of years, produced succulent fish for
the table. There was industry too, and a power station, close to the sea where the
river discharge was highest, took river water for cooling its plant and put it back
a few degrees warmer.
A few decades on, a 2 °C rise in temperature and a shift in rainfall towards the
winter had brought noticeable change in the landscape, but only small adjustments
in the culture. Central Europe had coped with centuries of political turmoil;
hotter summers, even the occasional whirlwind, were taken in their stride. Of
course everything had changed but always to a degree; as yet no cliff had been
fallen over. The snow lay only for a short time on the mountains; mostly it rained
and the downpours were often torrential. The flood defences had been
strengthened where the river abutted towns and villages, but not otherwise, so
that quite often the agricultural land was turned back to a flood plain in winter.
Not that this mattered much; the floods brought down a load of fertile silt from
the eroding mountainsides and the more damaging summer floods were rare, for
summers were now drier and hotter. There was much more maize growing and
even a couple of attempts at sugar cane, but really it was yet too cool for that.
The demands by government that more fuel come from biomass and ethanol had
encouraged experimentation, however.
The upstream reaches of the rivers dwindled in summer and occasionally dried
out. There was no longer a distinctive spring flood, just a modest rise when it had
snowed and the invertebrate and fish communities of the river had changed to
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