if you are middle-aged or older, you will likely know from personal experience how many natural places have been degraded since your childhood
Species are being lost on a global scale, the result of a combination of factors that includes the co-option of resources, the fragmenting and destruction of habitats, the introduction of non-native species, the spreading of diseases, direct killing, pollution, and the changing global climate. Documenting how many species have been lost is a non-trivial exercise: predicting how many could be lost by 2050 is even more so. However, if you are middle-aged or older, you will likely know from personal experience how many natural places have been degraded since your childhood. These trends can change, indeed it is quite remarkable just how much has been done, even if it falls short of the need. But, given the daily preoccupations that people face, persuading enough to demand action, and believe that this can be done without adverse consequences for them or others, is a challenge. However some major changes now appear inevitable, no more so that in high latitudes, where the anticipated changes to far warmer and wetter conditions will profoundly affect both people and wildlife alike.
Above: The reduction of Arctic Sea Ice volume, by month, since 1974 The summer Arctic sea ice has been melting at a remarkable rate over the last decade. Whether the accelerating decline since 2007 will continue, or whether it is an extreme blip on a longer trend, most experts believe that a summer ice-free North Pole is more likely than not at some point in the coming decades, as it was the last time CO2 levels were as high as today, before the last ice age in the mid-Pliocene 3.5 million years ago. Source: PIOMAS
some say we have created a new Geological Era
The changes to the Earth’s biology, chemistry and physics is leaving humanities mark in the sediments deposited under the oceans and on land. The changes are so dramatic that some say we have created a new Geological Era, the ‘Anthropocene’. The human induced changes to which we appear already committed (as it will take thousands of years for current CO2 levels to decline) are certainly extraordinary. This is no more evident than the Arctic Circle. The loss of Arctic ice has accelerated in the last decade (see graphic above). Satellite monitoring reveals the decline in the surface area, notably in summer. Even more significant is the rapid reduction in the total volume of the ice, according to PIOMAS. One 2012 assessment suggests the North Pole may became ice free one summer some time in the next decade. Other research suggest that, while this this will happen over the next 50-6o years, temporary stabilisation or even increases could happen in the coming years, overlaid on a long term ice decline. Either way is astounding, but not unexpected: the last time atmospheric CO2 was at current levels was in the Pliocene 3.5 million years ago, just before the last ice age, when forests extended to the Arctic Sea in Russia and North America. Summer temperatures at Lake El’gygytgyn, within the Russian Arctic Circle (the site with the longest unbroken record), reached 15-16°C (8 degrees higher than today) and annual rainfall was 600 mm (three-fold greater). The wider implications of this and similar research (summarised in the graphic below) are concerning, as they imply that the world may already be committed to temperature rises far greater in scale and impact than anticipated based on concrete evidence as well as computer models.
Actual and modelled land temperatures when CO2 levels were last equal or greater than those now expected. CO2 levels have been high in the past, most recently in the Pliocene just before the last Ice Age. They were then at or below the 450 ppm (parts per million) level that is the current policy target level, although 450 will be exceeded if fossil fuel use projections by the IEA materialise (see Energy section below). Both models (map colours) and actual fossils of plants and animals (coloured circles) generally indicate that air temperatures were above those projected for the +2°C policy target, exceptionally so at higher latitudes. To some the actuality of fossil records, and the story they tell, is convincing in ways that models are not. We should perhaps be particularly concerned about the implications of the combination of heat, rain, cloud and humidity. The disposition of land was then very similar to today, which wasn’t so in the Eocene, some 50 million years ago (still recent in the Earth’s 4.6 billion year history) when open sea passages between the Americas and through what became the Mediterranean might have made ocean circulation and heat transfer different from today. Temperatures were far higher, astonishingly so in higher latitudes. Then CO2 was in excess of 1000 ppm, more than double current levels. Source: data from IPCC Climate Change 2013 The Physical Science Basis, maps redrawn from Box 5.1, Figure 1.
PIOMAS also documents that ice cover in the Antarctic has grown in recent years. That is not necessarily a contradiction. The Arctic can be compared to ice floating on a warming bath. But much of the Antarctic is solid land. Rising global temperatures and increasing atmospheric water vapour, when temperatures will still be sub-zero in the Antarctic, might well result in increasing snowfall and subsequent greater ice cover in some parts. There are various competing hypotheses, including changes in wind strength and direction, that seek to explain the detail of what is happening in the Antarctic.
Will we simply adjust to the new normal? Except that it will be anything but normal …
If anything stirs people into action, then surely it will be open seas at the North Pole? ‘When hell freezes over’ means never, but ‘when hell melts’ was just as unthinkable. Or perhaps we will simple adjust to the new normal? Except that it will be anything but normal. The warming of the Arctic, and the reduction in the atmospheric and sea temperature gradient between the tropics and the pole, likely has major implications for weather and climate far beyond the Arctic.
Changes in the living environment, such as the loss of species, and changes in the physical environment, such as the loss of Arctic ice, are among the more obvious consequences of human actions. The various trends in those human actions, and the extent and the direction in which they might need to be bent if 9-10 billion are to live well, are explored below.
Source: Trends to Bend, modus vivendi, 2014, MMG