Changing climate and rising seas: Understanding the science
Changing climate and rising seas: Understanding the
During my seven years as Commissioner, I have consistently said that climate change is the biggest environmental issue we face. This investigation has provided an opportunity to develop a deeper understanding of what is causing climate change and one of its major and most certain impacts – the rising level of the sea. The aim of this report is to share that understanding with others to provide a basis for public engagement and policy development.
Over the last century, the average sea level around the world has risen by about 20 centimetres. The International Panel on Climate Change (IPCC) expects it to rise another 30 centimetres or so by the middle of the century and up to a metre or more by the end of the century.
There are three processes driving this rise – expanding seawater, retreating glaciers, and shrinking ice sheets. Thus far, the last – melting ice sheets – has contributed relatively little to sea level rise, but its potential is enormous.
A rising sea will be with us for a long time to come – one way or another we will have to adapt. But how high and how fast the water rises will be influenced by the speed at which the world – including New Zealand – reduces greenhouse gas emissions over the coming decades.