I was raised in the ‘long summer’, ruled by the dual natural phenomena of El Niño and John Howard. I didn’t know any different. Life was uncomplicated, life was good. It was all about paddlepops on the beach and hide-and-seek with the neighbourhood kids.

The El Niño Southern Oscillation (ENSO) is the major player in the year-to-year variability in global climate, especially for Australia. Basically, there is a perpetual see-saw between two states in the central and eastern tropical Pacific Ocean: El Niño (anomalous warming) and La Niña (anomalous cooling). Here in Australia, we call it the Southern Oscillation. And oscillate it does. We still don’t understand what tilts the balance from one to the other. We do know the consequences when it does. Like Eddard Stark at Winterfell, we are always reading the signs, looking for the clues that preclude the next big shift.

The ‘long summer’ of my childhood was typified by the 2000s drought (called the ‘Millenium Drought) that spanned 1995 to 2009, with some areas only recovering as late as 2012. Between 1980 and the mid 2000s, El Niño events dominated with only a smattering of La Niña events. You probably remember the frequent summer bushfires and winters that didn’t require heavy coats. Australia as a continent was battered and sun-blistered.

However, in the 1950s – 1970s, the opposite was true, with La Niña events exerting the predominant force on Australian climate. The carefree, child-like view of a stable planet becomes less and less palatable as you look further back in time.

Our planet is a complex, non-linear system that defies long-term modelling and predictions of biosphere stability. The last 650,000 years of Earth’s history have seen seven glacial cycles. The planet emerged from the last ice age approximately 7,000 years ago. The present interglacial period, the Holocene, represents nearly the entirety of documented human history from the onset of agriculture.

Instrumental records of temperature span only the last several centuries, a blip on the Earth’s 4.5 billion years of existence and tumultuous climate spectrum. The majority of our climate predictions are based on statistical analysis of just over 150 years of data. Paleo-environmental records including ice cores, dendrochronology and biomarker compounds in sediments provide a glimpse into the climate of the deeper past. The oldest records extend our knowledge of the Earth’s climate back 800,000 years. These records show that our planet has weathered enormous shifts in climate over its history. It has bounced from prolonged periods of global glaciation to conditions significantly warmer than present. Importantly, the continental record has indicated that climatic changes can occur quickly, in a matter of centuries or even decades.

During the Eocene, 50 million years ago, ocean temperatures exceeded 35 degrees Celsius in the tropics and the polar oceans were ice free at 12 degrees Celsius. Approximately 56 million years ago, the Earth’s climate system experienced a sudden, enormous release of carbon, equivalent to anthropogenic release of every last reserve of coal, oil and natural gas. Atmospheric carbon dioxide emissions exceeded 800 ppm. This event is known as the Paleocene-Eocene Thermal Maximum (PETC). The already warm climate system experienced temperature increases ranging from 5 – 9 degrees Celsius. This drastic change lasted nearly 200,000 years. The oceans bore the brunt of the consequences, with severe shifts in ecosystems, sea level rise and ocean acidification. If humans had been around, it is unlikely they would have been able to survive in the face of the extreme weather events caused by this shift.

The Holocene, the era of the humans, is a period characterized by relative climate stability. Yet even it has experienced several mild climatic shifts prior to the Industrial revolution with alarming consequences for human activities. These significant periods of climatic shifts within the last millennium are known as the Medieval Climate Anomaly (MCA) which broadly spanned the 9th to 13th centuries AD and the Little Ice Age (LIA), that occurred during approximately 1350 – 1850 AD. Both these events are well-documented for the Northern Hemisphere and affected seasonal crop productivity. The LIA was characterized by glacial expansion and prolonged cool conditions in Europe. Winter did indeed come. This period was preceded by the MCA, a period of unprecedented warm conditions comparable to modern temperatures. These unusual climatic periods occurred well before significant anthropogenic forcing, but the resilience of the Earth System has maintained key biogeochemical and atmospheric parameters within a stable range of fluctuation.

What goes around, comes around. Our understanding of what drives climatic change has dire consequences for the niche humans need for survival. The  PETM is a case study in the potential devastating, long-term effects of a sudden shift in climate. Over time, the Earth System re-attained equilibrium, but it took hundreds of thousands of years. The Earth is on the brink of a man-made PETM that is likely to have similarly devastating consequences. The planet will survive, but the continued survival of humanity is not assured.

Part of this shift will likely involve another plunge into semi-glacial conditions, with solar activity expected to plunge to 60% between 2030 and 2040. We should heed the Starks among us. We need to take urgent climate action.

Recent research has made it possible to estimate a safe operating zone for human life. Rockstromm et al, 2015 (read the latest paper here) identify nine planetary boundaries that regulate the resilience of our Earth System. These nine global priorities are highly subject to human influence. These nine processes are critical for the maintenance of natural systems in a Holocene-like state, the only known stable state amenable to human life. Drawing from the paleo-climate record, Rockstromm et al (2015) set theoretical limits on human-induced levels of change to these boundaries.

As of present, we have exceeded acceptable levels for four of these boundaries: climate change, change in biosphere integrity, land-system change and biogeochemical flows. Beyond the acceptable limits of these boundaries, the future of human existence on this planet is not assured. Climate change is the boundary that we have most seriously exceeded. With a threshold level set at an atmospheric concentration of 350 ppm carbon dioxide, we are already at 400 ppm and rising.

Australia is poised in a strong position to lead the charge by using the planetary boundaries framework, which requires novel and adaptive governance. Previously, we have taken minimal action on climate change. We’re not a nation that rushes into new things. While we can’t change the past, it does mean that we have the finances to implement industry measures to rein in emissions to meet the targets outlined in the United Nation’s Sustainable Development Goals (SDG). Australia needs to be strongly represented at the United Nations conference on climate change in Paris in December. Climate change, energy security and economic stability are all linked. Our government needs to pull it together to be taken seriously on the international stage by summer. Our future hangs in the balance.

It’s a shame it all feels like the Night’s Watch trying to convince the people of King’s Landing of the real threat beyond the wall. The people with power instead bicker over pointless nuances and scandals. The white walkers will come either way.



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