The world's leading climate science organisation has found no community or region anywhere in the world has avoided the impacts of climate change.

The latest report from the United Nations Intergovernmental Panel on Climate Change (IPCC) has warned of serious threats to the planet's ecosystems, infrastructure and agricultural production.

For the first time, the IPCC report focuses on the risks posed by global warming, concluding that in many cases the world is ill-prepared.

But the report also highlighted what governments can do to adapt to key vulnerabilities.

Speaking at the press conference in Yokohama, Japan, IPCC chair Dr Rajendra Pachauri said it was clear climate change had already had widespread impacts.

"We have assessed impacts as they are happening, impacts on natural and human systems, on all continents and oceans, and I would like to emphasise that in view of these impacts and those that we have projected for the future nobody on this planet is going to be untouched by the impacts of climate change," he said.

Chris Field, the co-chair of Working Group II, said it was clear climate change had already had widespread impacts.

Eight key risks identified 1. Low-lying coastal zones and small islands will be vulnerable to storm surges, coastal flooding and sea-level rises 2. More frequent flooding in urban areas 3. Breakdown in infrastructure and critical services such as electricity, water supply, health and emergency services due to increases in extreme weather events 4. Increase in deaths and illness due to extreme heat 5. Risk of food insecurity due to warming, drought and flooding 6. Significant drops in agricultural production and rural livelihoods 7. Loss of marine and coastal ecosystems with significant impacts on fishing communities and industry 8. Threats to native species and ecosystems

"Many of these have real consequences. Many of them occur in low latitude areas, high latitude areas, deserts, mountains, the oceans, the coasts really around the world," he said.

Mr Field said managing climate change needed to be understood in terms of managing risks.

"Too many times in the past we have conceptualised the climate challenge in finding out exactly what the temperature is going to be in exactly what year, and that matters much less than being smart about dealing with the things we know and the things we don't know," he said.

But Mr Field said the key message of the report was an optimistic one.

"There are a wide range of things that individuals, firms, governments can do to be smart about dealing with the climate challenge. Some of this involves mitigation and some of this involves adaptation.

"A good example is when you go to buy a new car. You are more than happy to pay for upgraded brakes and airbags, not because you think that you are going to crash on the way home, but because in the low probability of a crash you are as protected as possible," he said.

The Working Group II report details the impacts, risks and opportunities for action and adaptation, and lists eight key risks across the regions (see above).

The report highlights that adaption is happening in both the public and private sector and "that governments at various levels are starting to develop plans and policies and to integrate climate-change considerations into broader development plans".

Australian risk list identified

The World Heritage-listed Great Barrier Reef has topped the local risk list, with the IPCC warning that permanent damage is inevitable.

Australia's leading coral reefs marine scientist and lead author Ove Hoegh-Guldberg said mitigation strategies, such as improving water quality and reducing fishing pressure, will only "buy time" for the reef.

But he said he remains hopeful.

"We are at a point where we really are choosing a direction. If we delay any longer we won't have that choice anymore," he said.

"On one hand, we've got a hopeful and quite an optimistic scenario ... where corals will be doing [it] tough, but if we treat them right and get these changes going on, they'll survive."

While the report says planning for sea level rises and reduced water availability is getting better and is becoming more widely adopted in Australia and New Zealand, implementation is a little piecemeal.

However one of the lead authors, Professor Lesley Hughes, said there are opportunities within the report.

"It's not all doom and gloom if we get a wriggle on and do a lot about it," she said.

"If we have very strong mitigation, that is reduced greenhouse emissions, we can hope to stabilise the climate in the second half of this century."

The rigorous report process The report includes 310 lead authors from 73 different nationalities. Australian scientists are heavily involved as authors and reviewers of the Working Group reports. Lesley Hughes, the lead author of the paper on Australasia, says Australia "punches above its weight". "We are disproportionately a larger group than you might otherwise think based on our population in the IPCC authorship team," she said. "We have a lot of scientists working on climate change issues and that is because we see Australia as being particularly vulnerable to the impacts of climate change." The reports take up to five years to produce, undergoing a rigorous review process. For example, 48,000 review comments were received on the upcoming report. Professor Hughes says the process is not really a matter of achieving consensus, but rather is about evaluating the evidence. The Australasia chapter alone has 1,000 references.

The report has also singled out Australia's alpine region, which has suffered a significant drop in late-season snow depth at three of four alpine sites.

Ski resorts say they are already adapting but it will impact on the billion-dollar industry.

"For winter, our strategy is particularly focused around the snow-making capability," acting chief executive of the Victorian Alpine Resorts Coordinating Council Alex Shilton said.

"Over ... the last decade or so the machinery has been improved to the extent that it can cope with conditions that are perhaps not as favourable as it has been in the past.

"So they're able to make snow at slightly higher temperatures and slightly higher moisture conditions.

"Then we've got a summer strategy... [involving] things like downhill mountain bikes, road cycling events, festivals - that type of thing."

There might be more of those festivals, with the CSIRO predicting shorter ski seasons.

But there is still optimism from the industry.

"We had a really fantastic season in 2012 - it was followed up by a pretty poor season in 2013," Mr Shilton said.

"But we're like farmers. We're just used to dealing with the variability in the weather, the variability in the climate.

"It's just part of the business we're in."

International effort needed for 'global problem'

Environment Minister Greg Hunt said: "Australia is committed to addressing the challenges through direct and practical policy measures. This includes reducing emissions by 5 per cent from 2000 levels by 2020".

Scientists say that even if Australia acts on climate change, damaging effects could be felt locally if the rest of the world does not act.

Former United Kingdom government climate change advisor Nick Rowley said it is truly a "global problem".

"We shouldn't let that level of difficulty and challenge be an excuse for disengaging with it, because that will impose far greater cost," he said.

"If I were to stand around and say 'I'm going to increase taxes by 1 cent in the dollar and that will all go directly to school education', that would be very difficult to sell.

"But you could say it was about improving school education.

"In climate change, you can impose a cost, but you can't actually sell the benefit, because the reduction of emissions has to take place not only in Australia but in South-East Asia, in India, in Europe, in the United States."