This year, global temperatures have entered "unchartered territory" as they breach the one degree Celsius mark. That's according to scientists at the UK's Met office who confirmed that 2015 will be the hottest year on record:
"These are the highest temperatures we have seen in our record, which goes back to 1850. This is the first time we're set to reach the 1C marker and it's clear that it is human influence driving our modern climate into uncharted territory. We have passed the halfway mark to the 2C target."
The news came as the head of United Nation's weather agency Micheal Jarraudwarned that the Earth's climate is fast approaching a new "permanent reality". Concentrations of carbon dioxide in the world's atmosphere are expected to average 400 parts per million mark next year.
That represents a near 150% increase since pre-industrial times. According to scientists, 350 ppm is the safe level to avoid dangerous climate change:
"We can't see CO2. It is an invisible threat, but a very real one. It means hotter global temperatures, more extreme weather events like heatwaves and floods, melting ice, rising sea levels and increased acidity of the oceans. This is happening now and we are moving into unchartered territory at a frightening speed. "
The stark warnings come three weeks before world leaders gather in Paris to strike a make-or-break deal to rein in global carbon emissions.
Five years ago, heads of state promised to limit the warming of our planet to two degrees Celsius.
But, according to the United Nations, our planet is currently on track to warm by up to four degrees Celsius before the turn of this century. Such a temperature rise will usher in changes not seen since the last Ice Age.
The Met Office says that 4C of warming would be far more dangerous than simply doubling the impacts expected with 2C. In a 4C world, the 2003 European heatwave which claimed 70,000 deaths, would be "a rather mild summer".
According to the World Bank, unchecked climate change could push up to 100 million people into extreme poverty by 2030 as basic resources such as food and water slip out of reach.
And, although 146 nations have handed in their proposed emission cuts ahead of Paris, the sum total of bids tabled thus far will only limit global warming to three degrees Celsius.
"While this round of pledges is a step in the right direction, they only take us from a 4C catastrophe to a 3C disaster" says Tim Gore from Oxfam.
That means that the Paris accord must deliver tougher action later.
The news came as the heads of both France and China called for an "ambitious and legally binding" accord, and agreed that any deal must include checks every five years to ratchet up ambition.
Speaking ahead of the Paris summit, climate economist Lord Nicholas Stern warned:
"In human history it's a one-off. What we map out in the next two decades will be absolutely critical. Whether we can live in our cities - breathe in them, move in them - all of this will be defined by the decisions we take. I don't think the criticalness of these 20 years is sufficiently understood."
According to the French environment minister Segolene Royal, any new climate deal must raise the cost of burning fossil fuels: "I think that's what we have to do".
Royal would like to see a price of of €100 per tonne of carbon dioxide by the end of this century: "It's a good price," she said as higher prices will shift investment away from fossil fuels towards cleaner sources of energy. It's more than 10 times the current EU price for emitting CO2.
But, a global carbon price is not expected to be included in the final Paris treaty.
Nevertheless, according to one of the world's most influential climate scientists Professor John Schellnhuber, if the majority of nations honour their pledges, including China, the U.S., Europe, Brazil and South Africa, the shift towards a low carbon economy would become unstoppable:
"We will get a dynamic that will transform the development of the century. This is not sheer optimism - it is based on analysis of how incumbent systems implode. The avalanche will start because ultimately nothing can compete with renewables. If you invest at [large] scale, inevitably we will end up with much cheaper, much more reliable, much safer technologies in the energy system. It is really a no-brainer."
In a sign of things to come, green energy accounted for nearly 50% of all new power plants last year, and is now the second largest generator of worldwide electricity after coal. According to the International Energy Agency, clean power will overtake coal in the 2030s, marking a "clear sign that an energy transition is underway."
But, according to Schellnhuber, as there will be no international task force to enforce the Paris treaty, public pressure is "really holding the key to this. The last, best hope we have is moral argument."
And, much like the abolition of slavery, the spread of universal suffrage, and the U.S. Civil rights movement, great change is only possible when brave men and women stand up and fight for their rights.
As Thomas Jefferson once said: "Each generation needs a revolution." With a steep temperature rise sitting on our collective horizon, reining in climate change must be ours.