Wednesday, 26 August 2015

How Climate Change threatens the world's natural heritage

Not just Palmyra.

In July New Scientist reported that 35 World Heritage sites are threatened by climate change. That's nearly one in six of the sites listed because of their natural value. They include shrinking glaciers in Argentinia's Los Glaciares National Park and the washing away of birds nests by higher sea levels in Germany's Wadden Sea.

In  most cases climate change isn't the only factor. In Los Glaciares alien species, like cows and dogs, and increased visitor numbers create problems. In the Galapagos its much the same whilst in Mexico's Butterfly Biosphere Reserve commercial logging is a factor. Of course, these factors threaten that large majority of sites and habitats that aren't special enough to have World Heritage status but which are still important for the preservation of biodiversity and recreation.

Look behind the headlines and you see the same four causes:
  • More people - who need homes and food.
  • More prosperity - especially in China - which increases the demand for meat, minerals, travel, etc.
  • More development - both to meet local needs and to provide exports to the developed countries.
  • Unnecessary use of fossil fuels - driving climate change.
 Consumer capitalism has lifted billions out of poverty but it now threatens the natural world.

Can renewables meet the need?

A recent tweet celebrated the supposed fact that at peak, recently, Germany derived 25% of its power from solar. The source given was data published by the Fraunhofer ISE at  But is the claim true?

Actually no. The highest proportion in recent weeks was reached during August 2nd when a combination of low demand, low winds and strong sun produced about 56% of Germany's electric power from solar pv. A very good result - though obviously excluding fuels used for space heating, travel, etc.

But it's a power number - a measurement over a short time - specifically the middle of the day. There is no solar power at night and not much in the early morning and evening. A bit of rough analysis for a more representative day, 27 July in fact, shows that solar produced 22% of the power at peak but 10% of the day's energy. Extra investment in solar PV could increase the peak as much as you like - even to 100% - but that would still need over 50% of the energy to come from somewhere else (possibly wind or a storage system).

And this is mid summer.

A similar analysis for January shows a solar PV power peak of c8% but providing only c2% of the day's electricity. And the average over that week is much worse.

Is wind the answer? Sort of. Germany gets more energy from wind than from solar PV and it's available at night and in winter. But it's even less predictable than solar. At midnight on January 5th it provided just 3% of the needed electrical power.

Moreover periods of low wind can last for days - there was almost no wind for the whole seven days starting January 17th.

There are partial low-carbon solutions - nuclear, tidal, hydro, import of power from very large new solar farms in north Africa and various kinds of storage - but they all have their own problems.
Any responsible plan for our energy future must show how it would cope with periods like 17 to 14 January - and at what cost.

Sunday, 16 August 2015

Halfway to catastrophe!

Two weeks ago New Scientist reported the results of a kind of mini systematic review of global temperatures since 1850. In it Michael Le Page argues that the best baseline period - to give the temperature before global warming started - is 1850 to 1899. For convenience some temperature series use 1880-1899 as their baseline but this is misleading because temperatures in the 1880s were depressed by the eruption of Krakatoa.

When the five available temperature series are adjusted to use 1850-1899 as baseline it's clear that four of the five will show more than one degree of warming before the Paris IPCC conference this Autumn.

That's halfway to the the two degree level generally thought to imply a strong probability of catastrophic climate change.

Le Page continues with the prediction that unless we take "drastic action" the Earth will reach that two degree point by around 2050.