The causes and consequences of climate change and prospects for our future

Picture Credit: Banner via Flickr

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

The year 2016 was the warmest globally in records stretching back to 1850. The second warmest year was 2015 and the third warmest 2014. In recent years we have seen weather records being broken more and more often with severe heatwaves, floods and other extreme weather around the world. The risk of some of these extreme weather events has been shown to have increased as a consequence of climate change linked to human activities.

In the first talk of the Darwin College Lecture Series 2017, Dr Emily Shuckburgh discussed the scientific evidence surrounding the causes and consequences of climate change and the prospects for the future.

In her talk, Dr Shuckburgh gave examples of some of the extreme weather events which have occurred around the world recently. Flooding in the UK caused power outages and damage to infrastructure, hurricane Sandy devastated subways and homes in the US, and the summer heatwave in Europe in 2003 resulted in around 70,000 deaths.

Increasing temperatures and sea levels have resulted in a breakdown of the seasonal cycle, warming of the deep Southern Ocean and melting of the polar ice sheets. In the 20-year period between 1992 and 2012, two million km² of sea ice melted.

"If the Greenland ice sheet were to melt, sea levels could increase by 7 metres."

The lecture highlighted some very sobering yet compelling climate change projections. Doing nothing to reduce greenhouse gas (GHG) emissions could result in a 5°C increase in global average temperature relative to the period between 1850 and 1900, and a significant rise in sea levels.

"It is physically possible that everyone living in the world today could eat well and live more comfortably whilst reducing emissions to a level consistent with a 50% chance of 2°C warming. But to achieve this we need to transform the technologies and fuels we use."

With efforts to reduce GHG emissions, we could see an increase in global temperature of 1.7°C. However, keeping the temperature increase below 2°C, as stated in the Paris Agreement, will require current global carbon dioxide (CO₂) emissions to be reduced by 90%. For the UK, this means an 80% reduction in GHG emissions.

This lecture was part of the Darwin College Lecture Series. For information on other lectures in this series, please visit http://www.darwin.cam.ac.uk/lectures.