Evidence points to fundamental shift in climate


Changes will challenge our societal structures, and capitalism’s endless expansion in particular, writes PAUL GILLESPIE

TIPPING POINTS, paradigm shifts and critical junctures. These are some of the main concepts used by natural and social scientists to explain radical change. There is an interesting convergence between the different approaches, offering insights on current debates about climate change, global warming and extreme weather events.

All efforts to explain major change in big structures and large processes, by making huge comparisons, come up against the problem of how to interpret the relationship between particular events and longer-term trends.

Current discussions about the significance of the admittedly extreme drought in the United States corn belt and the persistently wet Irish summers focusing on the role of the transatlantic jet stream are a good example.

The jet stream flows between five and 10 kilometres above the E arth, determined by the border between cold Arctic and warm tropical air. Normally it moves north or south of Ireland, giving us a more varied summer, but for the last few years it has been locked in a position that gives us cool wet weather. The reverse is happening in the US.

Normality becomes an issue because climate scientists debate whether these events are more or less unusual. The US drought is the worst in 56 years and has had worldwide consequences for food supplies, while this summer has been one of the wettest in Ireland, although still within expected averages over 30 years.

But given the alarming news this week that the Arctic sea ice is about to reach its lowest recorded extent as a result of human-induced global warming, and knowing this will deeply affect climate patterns, it is perverse not to ask whether we are at a point that could trigger more radical change.

Climate change does not occur gradually but reaches tipping points fed by amplifying feedbacks that can hasten change and its consequences. Loss of the Arctic’s ice coverage in the summer decreases the Earth’s reflectivity, resulting in faster warming, with as yet unknown effects on weather systems.

Looking out on the Atlantic from Askillaun beyond Louisburgh in Co Mayo on a gloomy wet morning recently, it is hard not to take such warnings seriously. Michael and Ethna Viney add that another underestimated factor in these calculations is the North Atlantic Oscillation of the sea level pressure between Iceland and the Azores. Its barometric variation decides whether our winters are warm, wet and windy or cold and dry.

As they say in their fine book, Ireland’s Ocean, these issues are as yet poorly understood. Ireland is in a strong position to take the lead in researching them.

The evidence for tipping points in climate change is strong enough already. As Bob Watson, retiring chief scientist at the UK’s department of environment, says, the argument between scientists about whether we are at one is academic.

“There is no question the Earth’s temperature is warmer than it was 100 years ago. There’s no question we’re seeing more floods, more droughts, more heatwaves, all of which are totally consistent with the hypothesis of human-induced climate change, which points to the fact we humans are changing our environment.”

The term paradigm shift has become one of the most commonly used in discussions of scientific advance and organisational change. It was coined 50 years ago by Thomas Kuhn in his hugely influential book, The Structure of Scientific Revolutions.

He argued that major scientific change is not gradual but revolutionary or discontinuous. It substitutes one set of basic assumptions for another, after which a “normal science” based on solving these new puzzles becomes established. At a certain point sufficient inconsistencies or anomalies accumulate to make the old assumptions unwarranted, leading to a period of great uncertainty and debate over fundamentals.

Kuhn’s main case studies were in the transition from Aristotelian to Newtonian mechanics in the 17th century, but the lessons are much more general. They are not uncontested, of course, but offer huge historical insights on intellectual change.

In this perspective the relation between events and trends in climate research, and accompanying debates and controversies, becomes easier to understand. Climate change sceptics may have delayed the public appreciation of the subject, but accumulating evidence reinforces the impression that it is undergoing just such a paradigm shift.

It remains to be seen whether economic, social and political structures will undergo a commensurate change. In the language of the historical institutionalist approach to this subject, we are approaching a critical juncture in adjusting to the shifts in climate and their potential effects on humanity.

This too concentrates on periods of profound and rapid change that lay down parameters for the following periods of path dependence. What gets decided during these critical times will determine our future histories.

One very large question is left unresolved. Climate change means economic growth based on the unlimited expansion of capitalism is no longer viable. This is hard to communicate or admit during a recession, as we see in the US elections or euro zone crisis. This contradiction between the needs of ecology and capital will most likely dominate the coming century.


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