Climate and Humans: The Real Threats
There is geological evidence that global cooling with global ice ages occurred in the past when carbon dioxide contents of the atmosphere were more than double those of today, and evidence from anthropology and climatology, so well summarised in the recent SBS-aired program “How Climate Made History”, that there have been dramatic natural changes in climate throughout the history of mankind. Despite this, the concept that humans are strongly influencing climate is now firmly embedded in the global psyche. It is consuming billions of dollars in research to prove it and global meetings to discuss it, with arguments about whether reduction targets should be 1.5 or 2 degrees Celsius. This is despite the fact that natural changes of greater than 2 degrees Celsius are recorded over a decade or two from drill cores in lake sediments from the time of the Neanderthals and in the mediaeval mini-Ice Age in Britain in historical times, well before the Industrial Revolution. We should be far more concerned with a sudden return to Ice Age conditions, instead of our utopian interglacial conditions, because this would see massive crop failure at high latitudes and mass migrations to warmer climes that would make the recent refugee migrations in Europe seem like a picnic. According to some, our current interglacial period has already extended beyond its expected limit.
As there is now contention on whether global warming is occurring consistently over significant time spans, the human-induced global warming models have changed to those of human-induced climate change. Under this umbrella, all extreme events, whether hot or cold, dry or wet, windy or calm, can be placed at the door of human-induced low-percentage increases in atmospheric carbon dioxide due to burning fossil fuels. Is there really an increase in extreme events or is it an apparent effect caused by a switch from 1 hour news bulletins to 24 hour news services with stations desperate to report events in parts of the world that would go unnoticed by the western world 20 years ago, let alone 100 years ago? The reporters often say that this is the most severe storm or heatwave in a hundred years, with the implication that there have been more extreme events in the past. A good example was the situation in January 2015 which saw reporters scurrying to Marble Bar in the Pilbara of WA because it was predicted the maximum temperature would reach a record 50 degrees Celsius. Unfortunately, this was not a record because that was set in 1922 and was followed by a record heatwave in 1923-1924, close to 100 years ago. Interestingly, the highest temperature recorded on the planet was at Death Valley in California in 1913, almost exactly 100 years ago. In fact, we often use the term “hundred year event”, because these events are one of several normal Earth cycles due to complex factors such as interactions between the tilt of the Earth’s axis and its rotation around the Sun as the Earth wobbles through the solar system
What I think is clear is that humans are a major cause of the disasters that arise from extreme weather events, simply because of population explosions allowed by a combination of the Industrial Revolution and its associated technology and a utopian warm climate. For example, Perth has approximately 20 times the population it had in 1915. We build ever increasing numbers of towns and cities on flood plains, which, by definition, flood to replenish the soils on the plains, often with extreme floods every 50 to 100 years. The floods in 2011 in Brisbane represent a case in point, where part of the city has been built on a flood plain and the population has increased to almost 17 times that of 1915. The houses and infrastructure severely restrict the area of the flood plain surface in a town or city, such that the same volume of water that once spread uniformly over the plain will be restricted and locally rise higher in the built-up area and flood it. We build tourist resorts at sea level that can be flooded during anomalously high tides or tsunamis that have occurred throughout history. We cut down trees on steep hills, causing landslides during extreme events. So, although many believe that we are inducing climate change, it is more important to realise that we are causing disasters relating to natural events because of population increase and habitation of environments that ancient peoples in equilibrium with their environment would have avoided. The ancient Egyptians, for example, farmed the flood plain of the Nile and lived and built their monuments on the adjacent desert.
It is doubtful that climate change involving mild global warming will drastically change our lives overall: there will be losses and gains dependant on geographic location and latitude as there have been throughout history. Sea level changes are normal. When the aborigines migrated into Australia, the coastal plain would have extended out to Rottnest Island, and there is evidence on our northern beaches of a rise of about 2 metres above current sea level since then. A global cooling event, while reducing sea levels would be disastrous for populations at high latitudes or those in the Indian subcontinent, for example, dependant on water from melting alpine snow and ice. Our greatest threat is catastrophic short-term climate change from eruption of super-volcanoes which would cause blockage of the Sun’s rays and a year-long winter with ensuing crop failure and famine throughout the Earth. The Earth’s plates are aligning such that we can expect more volcanic eruptions and earthquakes with associated tsunamis in the future. Our priority should be to plan how to survive such events with long-term food supplies, with current global supplies running out over a relatively short time span. We should also be concerned about the Sun, undoubtedly the major control on our climate. If there were a giant solar storm, it could knock out all satellites and most power plants, crippling our digital world in “The Digital Apocalypse” as described in my novel of the same name.
So, the real question is: “Should we be spending our energy and billions of dollars on human-induced climate change, in the quite arrogant belief that we can change climate, or should we be more concerned about natural climate changes that have occurred throughout human history and could result in our near-extinction unless we are prepared for them”. It is like our personal lives. We can adapt to gradual incremental change, but it is the sudden tragic events in life that exact their toll, just as such sudden events have probably caused extinctions of species in the past.
Dr David I Groves