Climate change threat to world future

Climate change scientist Jim Salinger's predictions for the future make sobering reading.

Jim has recently published his latest book Living in a warmer world. He came to Nelson as part of the Arts Festival to speak about his book, which brings together contributions from other leading scientists to describe how a hotter planet is affecting our food supplies, fisheries, agriculture, fresh water and public health.

Jim discussed what he believes society needs to do to, and the political and ethical issues around the changes we need to make.

Jim worked for the Crown Research Institute National Institute of Water and Atmospheric Research (NIWA) until 2009 and was a lead author for the Intergovernmental Panel on Climate Change which was awarded a Nobel Peace Prize in 2007.

He takes two minutes from his busy schedule to speak with The Leader.

We've just seen a huge typhoon hit the Philippines causing massive death and destruction. What's the prognosis for more extreme events over the rest of our lifetimes?

From a climatological perspective, averaging estimates gives it a strength of 305km an hour after landfall, making it [Cyclone Haiyan] the strongest tropical cyclone on record to make landfall in world history. With a warming world, the prognosis is for less typhoons or tropical cyclones, but with more intense winds making cyclones such as Haiyan more common.

Projections for a 4°C world show a dramatic increase in the intensity and frequency of high-temperature extremes. Recent extreme heat waves such as in Europe in 2003 (70,000 deaths) and Russia in 2010 (55,000 deaths) are likely to become the new normal summer in a 4°C world.

Extreme heat waves in recent years have had severe impacts, causing heat-related deaths, forest fires, and harvest losses. Droughts will become more frequent. For New Zealand a 1 in 20-year drought will become a 1 in 2 to 5-year drought, so droughts like that of last summer will become much more common.

Tell us why you produced your book?

As I have been watching climate change since the mid-1970s, watching the world warm up, I decided it was time to document the changes that have taken place, and the likely projections of what will occur.

Over this time period the world has warmed by almost 0.5°C, and is projected to warm a further 3°C or more during the 21st century, if we act on climate change. But current pledges from governments put the world on a track to reach 3.5 to 4°C by 2100. Nature is now giving many signals. Globally, our water, food systems and health are both changing and going to change dramatically. It is very important to document the changes.

I think the world experts in the book communicate the implications of these in a very readable way - to a lay audience.

What are a few facts in the book that would surprise most readers?

Perhaps the most surprising new information for New Zealand is the rate at which our glaciers are shrinking. From 1977 to 2008, the glaciers in the Southern Alps shrank by 16 per cent. While researching my chapter, written with Trevor Chinn, we found that the loss has now almost doubled. We have lost 14 per cent of our Southern Alps glaciers in just four years (30 per cent since 1977).

The food chapter documents the changes occurring to viticulture. The chapters on pastures and livestock show how this form of food production will still be a vital source of protein to feed millions of people, and the marine fisheries chapter shows that a warming is changing distribution of fish and abundances.

You and many others have dedicated your life to studying climate. What do you say to those who don't believe the evidence?

The evidence of a warming world and that humans are responsible is undeniable. Concentrations of atmospheric carbon dioxide have reached 400 parts per million as a result of human consumption of fossil fuels and deforestation.

Last time carbon dioxide was at this level was 3 to 5 million years ago and human civilization did not exist. Surface temperatures are 0.7°C warmer than a century ago. The oceans at depth have been warming rapidly, and Arctic sea ice at the September minimum has diminished 30 per cent since 1979.

Mountain glaciers of the world have lost an estimated 14 metres in their thickness since the 1950s. The evidence is very compelling.

What is one New Zealand and/or international government policy you would change?

Making mandatory emissions reductions targets of 20 per cent by 2020, and 60 per cent by 2050 with electricity generation being entirely renewable by 2020.

New Zealand is a lucky country with abundant renewable energy resources so these targets will be able to be reached with ease.

You caused a stir in 2009 when you were dismissed from NIWA for speaking directly to the media. What's the relationship between scientists and the media like these days, and how could it improve?

Government scientists are controlled in their interactions with the media, because they are employed in Crown-owned companies, with independent boards of directors and a management structure akin to private companies.

University scientists are independent. People get most of their information about science from the news media and, in the past the general public have not been warned of physical risks, or told of actions to reduce those risks of climate change.

News framings of the risks of climate change have been represented as political but not physical (watch the next two week's Conference of the Parties to the United Nations Framework Climate Changer Convention in Poland), and as a problem for "others" but not "us".

The way forward is for journalists to re-consider obligations to audiences and for science communication to include the media. Journalists should also read the Intergovernmental Panel on Climate Change reports and use the information.