Global warming has gained unstoppable momentum and could dramatically exacerbate a host of challenges already facing its creators, humans, if not properly managed.

"There is a less than 10% chance that the climate changes we see are due to anything but past human activity," says UCT's Professor Bruce Hewitson of the Climate Systems Analysis Group in the Department of Environmental and Geographical Sciences. "The magnitude of climate change can potentially be managed, but it cannot be stopped."

Hewitson is a co-ordinating lead author of the Working Group One Report, Climate Change 2007: The Physical Science Basis, of the Intergovernmental Panel on Climate Change (IPCC). The IPCC released the report, the work of some 600 authors from 40 countries, in Paris in early February.

The document caused a stir when it said that global warming is "very likely" (more than 90% probability) caused by man. This marked an escalation from the panel's last report in 2001, which then described the connection as "likely".

It also warned of continuing temperature and sea level rises, and changes in weather patterns.

The problem, Hewitson says, is largely the excessive and inefficient use of fossil fuels, resulting from an energy dependent society. Greenhouse gas emissions (where gasses, like carbon dioxide, are released when fossil fuels are burned) give rise to elevated global temperatures. With mushrooming populations and developing countries trying to catch up with the First World, the problem, Hewitson believes, is rapidly intensifying.

What does this mean for South Africa?

Here, the East Coast will get wetter and the West Coast dryer, says Hewitson. Temperatures rise everywhere, and the frequency of weather events change. The most ominous threats for Cape Town are the predicted impacts on water resources and agriculture.

There are two key responses needed: reducing global greenhouse gas emissions, and adaptation and improved resilience to the changes we are already committed to, Hewitson says.

"We need to manage climate change to avoid reaching tipping-point crises."

But the power is in the hands of policymakers. Hewitson suggests proactively developing policy and adaptation, with investment in key areas like water resources and health, and targeting issues that are heavily dependent on the climate.

There is also a critical need within South Africa to grow the size of the scientific community addressing climate change - educating, training, and most importantly, retaining new scientists within the region, backed by solid investment in communication frameworks between scientists and stakeholders.

"Our government is making all the right noises," says Hewitson. "Translating those noises into action is now the challenge."