BELOW: a man looks on as a wildfire reaches his house near Mangualde in Portugal in August w orldwatch
Humanity has kept the world’s wildfires in check for the past century, but we may be about to put nature back in control, according to a new model of global wildfires.
hanks to charcoal layers in sediments and methane concentrations in ice cores, we have a good record of past wildfire activity. This record shows dramatic fluctuations over time; for example, there was a significant lull between 1600 and 1750, followed by an unprecedented surge beginning around 1800. This was followed by a rapid decline beginning in 1900 that has continued until the present.
Previous models of wildfire activity have struggled to explain these fluctuations, in part because it’s difficult to tease out the effect that humans have had on both igniting and suppressing wildfires. The present model, developed by NASA researchers Olga Pechony and Drew Shindell, is the first to successfully replicate the past 1,000 years of wildfire history. The scientists used data from a number of satellite instruments to validate the model, including information on precipitation, vegetation and lightning and fire activity. When Pechony and Shindell combined the model with an existing climate model, they were able to simulate future wildfire trends under a range of different climate regimes. The results suggest that there will be large increases in fire activity in India, Australia, central Asia and Siberia, southern Europe and southern Africa. ‘Our projections show that our rising temperatures – this time driven by humans – are on the verge of reasserting control over the world’s fires,’ Pechony said.
n Ancient insects rewrite Asian palaeogeopraphy: A huge haul of amber, containing hundreds of prehistoric insects and other organisms, has shed new light on the ancient geography of India and South Asia.
ecovered from a coal mine in the Khambhat region of Gujarat in western India, the 150-kilogram haul contains more than 700 fossilised arthropods (invertebrates with a jointed body and limbs and a hard exoskeleton) from at least 100 different species, including ancient ants, termites, bees, spiders and flies. The creatures date back to around 52 million years ago, before the collision of India and the Asian plate.
he amber provides the oldest evidence of tropical forests in Asia, tests having linked it to hardwood trees belonging to the Dipterocarpaceae family, which today make up 80 per cent of the forest canopy in Southeast Asia. More intriguingly, however, they offer evidence that a chain of islands may have linked India to the Asian mainland at the time.
India split off from Africa around 160 million years ago and then spent the next 100 million years moving towards Asia at a rate of 20 centimetres a year. This would have been long enough for arthropods trapped on the Indian landmass to evolve into a suite of unique species, but the encased organisms are closely related to Asian and European species.
‘Our findings suggest that the mixing of fauna was already so strong that it was already happening for several million years,’ said Jes Rust, a palaeontologist at the University of Bonn and one of the study’s authors. He and his collaborators suggest that the imminent collision between India and Asia may have created an arc of islands that connected the two landmasses like stepping stones.
14 www.geographical.co.uk december 2010