New climate change alert

THE red hand of climate change is creeping ever faster. That's the message from the first report, just out, of the Fifth Assessment by the International Panel on Climate Change (IPCC), arguably the most important scientific document of our time.

The assessment considers the latest scientific evidence as a basis for climate change, how we can best adapt to it, how its effects can best be mitigated and the greenhouse gas emissions which are driving the problem through primarily burning of fossil fuels and clearing of land for development, agriculture and housing.

Published this week, the first report on the scientific basis for climate change was compiled by 259 lead authors from 39 countries. It consists of 2500 pages of text, and draws on millions of observations and more than two million gigabytes of data from climate model simulations. More than 9200 scientific publications are cited.

The co-chairman of the working group which compiled the report, Qin Dahe, says observations of changes in the climate system "are based on multiple lines of independent evidence. Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased."

Warming of the climate system is unequivocal, the report says. Each of the last three decades has been successively warmer than any preceding decade since 1850.

On page 33, as South African climate change specialist Prof Guy Midgley, from the South African National Botanical Institute, pointed out to me, there is a particularly important graph.

It shows that, on mankind's present carbon trajectory, planet Earth will by the end of this century hit 4°C warming over pre-industrial times.

The IPCC has already spelt out what that would mean – in such a world there would be "a new class of heatwaves that would make 40°C a pleasant prospect".

A 4°C temperature rise by the end of the century would likely trigger declining global food stocks and sea level rises affecting hundreds of millions of people, severe water shortages, swelling disease loads and no certainty that any adaptation would, at that stage, be possible.

This scenario is still more grim for Africa, Midgley notes.

Global warming estimates include the cooler temperatures over the oceans.

Land temperatures are always higher and Africa's geographic and meteorological position means the present global development path could take us to well over 5° higher temperatures by the end of the century. High poverty levels and deteriorating ecological buffer systems would increase our vulnerability.

Ice sheet loss multiplied through the period 1992 to 2001 compared against 2002 to 2011, the report says. In Greenland it leapt from 34 gigatons per year to 215gt/yr. In Antarctic it increased from 30gt/yr to 147gt/yr.

Related to this phenomenon, a global sea rise of 30cm to 80cm can be expected by the end of the century. This may not seem like much but, as Midgley explains, application of the Bruun Rule – where 1cm rise in sea level erodes beaches about 1m horizontally – indicates the severity of what could occur. Add onto this storm surges as we saw in 2008 along the eastern and southern Cape coast, and the threat multiplies.

As grim as all this news is, it could be worse if the study period for the fifth assessment did not straddle a La Nina phase.

This natural variability means cooler conditions and we can expect "another strong step upwards" in climate change when we enter the next warm El Nino phase, he says.

The last one helped the 30-year bloc 1983 to 2012 to be the hottest in 1400 years.

The flipping of these phases cannot yet be forecast and it is one of the many factors which makes climate science so complex.

But what is clear is we do not need to proceed on the road to doom we are travelling at present.

We can instead keep that temperature increase to just 2°C and see the benefits by mid-century, Midgley says.

To accomplish that we need an international agreement where competitive advantage and risk for countries are equally apportioned to especially the top five carbon polluters.

It's a team game and if we don't achieve that deal, we will all go down the tubes.

With the new Australian government having already ejected many of its progressive climate change measures and a country like Japan now ambivalent where it was once a leader with the Kyoto Protocol, South Africa can lead by example in the Brics and Group of 7 forums.

At home, the government has produced a climate change response white paper which envisages a "peak, plateau and decline" for carbon emissions, Midgley notes. Conflicting energy policies have allowed for renewed focus on coal power and a carbon tax on high-end car users.

Ordinary South Africans need to inform themselves about climate change, change their own lifestyles and demand a faster move up to and over that plateau, delivering a green energy system, so these taxes will not be necessary, he says.