Has climate change become an existential threat?

10 May 2017


Reported by Anna Fee, NERC-funded CSaP Policy Intern (January-April 2017)

In the final climate seminar of the series, Professor Veerabhadran Ramanathan, Professor of Atmospheric and Climate Sciences at the Scripps Institution of Oceanography, UCSD, explains how climate change may have become so serious that we may now be facing an existential threat.

Professor Ramanathan had a sombre but important message for the audience; ‘climate change is slowly slipping out of our hands’. The International Panel for Climate Change (IPCC) has claimed that a global warming of the planet above 1.5 °C is ‘dangerous’ but recent climate model projections indicate that temperatures will have exceeded 2 °C by 2050 due to the 3 trillion tonnes of carbon dioxide being pumped into the atmosphere.

This temperature increase is amplifying other natural feedbacks. Every 1 °C increase in temperature increases ocean evaporation by 6-15%. Between 1979 and 2012, 40 % of the Arctic sea ice melted. As a result, dark ocean water is now absorbing solar radiation where ice was once reflecting it. The retreating sea ice is also weakening the transfer of oxygen from the atmosphere to the oceans, causing the oxygen content of the oceans to decrease which may lead to more extinctions of animal species.

Professor Ramanathan identified the top 1 billion of Earth’s population as being responsible for 50% of current CO2 emissions through unsustainable consumption of fossil fuels. The European heatwave in 2003 caused 70,000 premature deaths. Temperatures above 35 °C cause humans to enter hyperthermia. The existential threat posed by climate change will hit the poorest 3 billion of the global population who are already dying from inhaling cooking smoke.

'A global 7 °C temperature increase could cause a third of the planet to become uninhabitable.'

He presented a two lever approach to prevent warming exceeding 2 °C. Firstly, we need to reduce carbon emissions using the technological solutions available to electrify sources of CO2 such as cooking and heating. This can help us ‘bend the curve’ of climate change by 50% but we need to change our societal behaviour too. The second lever involves curbing production of short lived climate pollutants such as methane, black carbon, hydrofluorocarbons (HFCs) and ozone. If we are to stay in the ‘safe zone’ which may still involve a 1.5 °C temperature increase, starting from 2030, we will need to remove 60 billion tonnes of CO2 per year for the next 60 years. This is achievable, in Professor Ramanathan’s opinion, but will require immense public support.

(Banner Image Courtersy: Ben Salter via Flickr. Thumbnail Image Courtesy: Nicolò Lazzati via Flickr.)

  • 26 January 2017, 5:30pm

    2017 Christ's College Climate seminars

    What institutional arrangements, knowledge and politics are required to tackle climate change in the coming decades? Professor Charles Kennel and the Centre for Science and Policy, in conjunction with Christ’s College, will deliver the next climate change seminar series.