5 reasons why climate change may be worse than we think

This article, authored by Climate Councillor Professor Will Steffen, originally appeared on the World Economic Forum Blog.

Goal 13 of the Sustainable Development Goals is about taking urgent action to combat climate change and its impacts. Superstitious about the number 13 or not, climate change really will be unlucky for some people; if we do not control the problem it will be devastating for all.

Here are five areas of concern:

1. Severe impacts of climate change are happening now.

With “only” a 0.85°C rise in global average temperature, we are already seeing changes in extreme weather and this is driving the most damaging impacts. The frequency and intensity of heatwaves have increased in Europe, Asia and Australia. The global water cycle is intensifying. More places around the globe are being hit by more rain and heavier rain, including Europe and North America, while some regions have seen increases in the duration and intensity of drought. Intense tropical cyclone activity has increased in the North Atlantic.

2. The polar ice sheets are melting at accelerating rates.

Along with a warming ocean, this is driving up sea levels at an increasing rate. The frequency of coastal flooding is already rising, and approximately trebles for every 10cm of rise in sea level. In a rapidly urbanizing world, many of the largest cities and their critical infrastructure are located on vulnerable, low-lying coastal areas. Sea-level rises of 1 metre or more by the end of the century – the upper end of the estimated range by the Intergovernmental Panel on Climate Change (IPCC) – would threaten the livelihoods of tens or hundreds of millions of people and would wreak havoc with the global economy.

3. The risk of abrupt, irreversible changes looms ahead.

Perhaps the most dangerous aspect of a rapidly changing climate system is the risk of crossing large-scale tipping points, which could not only cause severe, direct consequences for human well-being, but also drive strong reinforcing feedbacks in the climate system that further accelerate climate change itself. We are approaching several significant tipping points in the climate system: the irreversible melting of the Greenland ice sheet, which holds enough water to raise sea level by 7 metres; large-scale emission of CO2 and methane from thawing permafrost, which by 2100 could pour the equivalent of 25 years of human carbon emissions into the atmosphere; and the transition of the Amazon rainforest to savanna.

4. Climate change is a threat multiplier.

The impacts of climate change can exacerbate other stresses, like poverty, economic shocks and unstable governments, to make crises worse. For instance, increasing extreme weather events can reduce the availability of food. Drought contributed to the 2008–2009 and 2010–2011 food price spikes, which likely affected socio-political stability and contributed to food riots in the Middle East.

5. The more we learn about climate change, the riskier it looks.

A comparative analysis of the last three IPCC reports, spanning the period 2001 to 2014, shows that as the science improves, our assessment of risk changes. Severe impacts from extreme weather, the disproportionate impacts on developing countries and poor communities, and the threats to unique ecosystems and species now loom larger than they did a decade ago. The scientific underpinning for the 2oC policy target as a “safe” level of climate change is now weaker than it was a decade ago, and the scientific case for the 1.5oC limit is more consistent with our current level of understanding.

Climate change is far more than just an environmental issue; it fundamentally changes our relationship with food and water, which is essential for our well-being and for the viability of nearly all other forms of life. We have collectively built and optimised all of human civilisation for the relatively stable climate that has existed for thousands of years. That climate is now changing rapidly. Without urgent and effective action to curb greenhouse gas emissions, the long-term impacts of climate change could be massive, abrupt and disruptive to a planet currently carrying over 7.3 billion people, all of whom want, expect, and have a right to a decent and safe standard of living.

If we don’t get goal 13 right, it will be unlucky for all the others.

Author: Will Steffen, Councillor, Climate Council of Australia, Emeritus Professor, The Australian National University, Senior Fellow, Stockholm Resilience Centre

Guest editor of this series is Owen Gaffney, Director, International Media and Strategy, Stockholm Resilience Centre and Future Earth

Header image: Adelie penguins stand atop ice near the French station at Dumont d’Urville in East Antarctica January 22, 2010. REUTERS/Pauline Askin

Sustainable Development Goals image: Jakob Trollbäck