Why it is a climate emergency

From Climate Code Red:

Since mid-2018, understanding of the climate emergency has exploded globally. Everybody is talking about it. The Oxford Dictionary named “climate emergency” as its Word of the Year for 2019, and more than 1100 national, regional and local governments in 25 countries have declared a climate emergency.


Understanding of the emergency and the existential risks have been driven by many factors, including: the local government campaigns; Greta Thunberg’s brutally direct language and the StudentStrike4Climate movement; and the advocacy of The Climate Mobilisation in the US and Extinction Rebellion; and campaigns such as those for a Green New Deal.


Turning recognition of the climate emergency into an emergency plan and mobilisation around the world is the only strategy that matches ambition to the scale of the problem. But what does this phrase “climate emergency” mean?

In 2008, Philip Sutton and I deployed the phrase in a book: Climate Code Red: the case for emergency action. As we described it the book, at emergency response is one in which:

• Immediate, or looming, threat to life, health, property, or environment is perceived;

• High probability of becoming overwhelming if immediate action is not taken ;

• Speed of response is crucial;

• The crisis is of the highest priority for the duration;

• Bipartisanship and effective leadership are generally the norm; and

• All available/necessary resources are devoted to the emergency
.

Australia’s Prof. Will Steffen says  climate should be “the primary target of policy and economics” with something “more like wartime footing” to roll out the transformation “at very fast rates”.

This idea is important because at just 1.2°C of global average warming so far, climate change is already dangerous:. Here are five examples:

• Three-quarters by volume of Arctic sea-ice has already been lost, the Arctic ecosystem is fundamentally changed 


• One-quarter by volume of the Himalayan ice sheet has already been lost, yet more than a billion people rely on it for water.


• We have already crossed tipping points for the loss of large West-Antarctic glaciers and a sea-level rise of several metres. 


• Three quarters of the Great Barrier Reef has been lost.  At the present temperature, it is likely to bleach every 3-4 years, but recovery time is 10-15 years. This is a death spiral.


• Already many of the most densely populated regions of are suffering from high levels of water stress. 1.8 billion people will be living in water-scarce regions by 2025.

So 1.5°C is not a safe or reasonable goal. In the longer run, sea-levels rise 10-20 metres for each one degree rise. 


1.5°C is just a decade away, a consequence of past emissions.  and there is no carbon budget for 1.5°C.  Nothing in the short-term bar geo-engineering — the use of sulfates to provide some temporary atmospheric cooling  —  will keep us under 1.5°C. But such approaches have not yet been demonstrated to be of net environmental or social benefit. 


So this is one line of evidence for climate emergency: 1.5°C is dangerous, and close at hand, and very difficult to avoid.

A second line of evidence comes from our climate history. The last time atmospheric carbon dioxide emissions were at the current level was during the early-to-mid Pliocene 3–4 million years ago, when temperatures were around 3°C warmer than the late 19th century, and sea levels were around 25 metres higher.


A third line of evidence comes from the 2015 Paris agreement.  If the current commitments by nations to reduce their emissions are not greatly improved, we face catastrophic warming of 3°C within a lifetime and up to 5°C by century’s end, according to the World Meteorological Organisation.


But scientists say warming of 4°C is incompatible with an organised global community, is devastating to the majority of ecosystems, and has a high probability of not being stable. National security analysts say that at 3°C the international order between nations may break down into “outright chaos”.


And here is why: 3°C threatens to make large parts of the world and food-growing lands uninhabitable. This includes regions ruined by drought and desertification, areas too hot to live in year-round, and rising seas.


On 27 November 2019, in the journal Nature, leading scientists wrote: “we are in a climate emergency… this is an existential threat to civilization.”   An existential threat to human civilisation, that is, ordered societies, not to the species as a whole, that is human extinction.  But we are currently on a path of warming that is an existential threat to contemporary societies..


A fourth line of evidence is the proximity or more tipping points, that is, the passing of critical thresholds which result in step changes in the climate system that are irreversible on human timescales without herculean human interventions.

As one example, that recent Nature paper pointed to “biosphere tipping points which can trigger abrupt carbon release back to the atmosphere.. Permafrost across the Arctic is beginning to irreversibly thaw and release carbon dioxide and methane… the boreal forest in the subarctic is increasingly vulnerable.”  They say that “Other tipping points could be triggered at low levels of global warming… a cluster of abrupt shifts between 1.5°C and 2°C…”. And remember 1.5°C is just a decade away.

In the chart, the circles show annual temperature anomalies, the black line the 5-year moving average and the red line the 10-year moving average.  So we are now already 1.1 or 1.2 degrees C above the level at the beginning of the industrial revolution.  If temperatures continue to rise by 0.2 degrees per decade, we'll reach 1.5 degrees by 2040, and 1.7 by 2050.  And that assumes we start cutting emissions now.