Three years ago, the United Nations commissioned the world's top scientists to find out if global warming can be limited. This week, the Intergovernmental Panel on Climate Change (IPCC) published their report, saying that it is possible to limit global warming and prevent a climate catastrophe.

The report is seen as the main scientific guide for government policymakers on how to implement the 2015 Paris Agreement, which aims to limit the rise in global average temperatures to "well below" 2 degrees Celcius above pre-industrial levels, while seeking to tighten the goal to 1.5C.

"The report maps out how much worse it would be if we get to 1.5C, how much worse again if we get to 2C. Some of those numbers are striking," says Michael Grubb, professor of energy and climate change at University College London.

"The report estimates that with 1.5C warming we'll lose something like 70-90 percent of the world's coral reefs. If it goes up to 2C, then we're talking about [losing] 99 percent. Those kind of statistics give you a sense of what we're dealing with, similar to the change of the Arctic ice."

The IPCC says we can limit global warming and prevent a climate catastrophe - but there is a deadline. One which critics say is not technologically feasible or economically practicable.

Meeting the 1.5C target will require a 45-percent cut in carbon emissions by 2030 and building a global net zero carbon emissions economy by 2050.

If you're putting money into coal power stations or mines, you're taking a huge strategic risk on all fronts.

Michael Grubb , professor of energy and climate change, University College London

Melissa Price, the Australian environment minister, was quick to respond to the report, saying she's more focused on bringing down electricity prices than phasing out coal. Of all the different types of fossil fuel, coal produces the most carbon dioxide - and Australia is the world's biggest producer.

"In terms of any investors listening, my first advice would be, if you're putting money into coal power stations or mines, you're taking a huge strategic risk on all fronts," says Grubb. "Whether it's local air pollution, global, the general pressures, coal is the first in the line of fire, and we've seen dramatic reductions in the UK, much of Europe, and even North America."

As things stand, decarbonising the world's electricity system fast enough to meet the IPCC's targets would involve, at the very least, global consensus, a major paradigm shift, and trillions of dollars.

"One of the big changes in the political dynamics in the last 10 years has been the Chinese position. They're emitting substantially more now than the United States. But what has really shifted the politics in China has been local air pollution," says Grubb.

"What we see is a tremendous drive from the central government to try and close down old and inefficient coal power stations, put clamps on what had been a massive programme of coal power station construction."

"Beijing has basically banned coal burning in its regions and is now set to ban petrol-driven cars because of the local air pollution. What I see is a big shift in terms of both its energy policy and its geopolitical positioning to say, 'Of course, China has to be part of the solution and we intend China to do well by being involved in the emerging clean technology businesses'."

Also on this episode of Counting the Cost

Africa's cities: Africa's population of roughly 1.1 billion is expected to double by 2050, with more than 80 percent of that growth occurring in cities. The UN projects that 10 of the world's fastest-growing cities over the next 17 years will all be in Africa. Eight African cities are expected to more than double in population size in the next few years. The continent's top three fastest-growing cities are Dar es Salaam, Nairobi and Kinshasa.

WATCH: Africa's urban explosion (3:51)

"On the good side, as these cities will get bigger, they'll have a more conglomeration of benefits that potentially can increase productivity that cities offer. We know that in Africa that families moving to big cities probably double their household incomes and job opportunities for all the people in the household. But the challenge is being able to manage that population growth and have livable cities," says Vernon Henderson of the London School of Economics.

Nobel Prize winners: The Nobel Prize for economics went to William Nordhaus of Yale University and to Paul Romer of New York University. Nordhaus, who has been called "the father of climate-change economics," has argued that nations must raise the price of fossil fuels to protect the climate. Romer, a growth theorist makes a compelling case for governments and companies to invest in research and innovation to tackle the crisis, as Charlotte Bellis reports.

Zimbabwe medical shortages: The International Monetary Fund (IMF) and World Bank have approved plans for Zimbabwe to pay back more than two billion dollars in debt, a vital step to secure new loans to revive the economy. The government recently imposed a tax on bank transactions that has been blamed for raising prices and causing shortages, severely affecting the health sector, as Haru Mutasa reports from Harare.

Illegal wildlife: Stopping global wildlife smuggling and protecting some of the world's exotic species from extinction is the main aim of a summit in London. It is estimated that the global wildlife trafficking market is worth up to $23bn a year, as Nick Clark reports from London.

Source: Al Jazeera News