Piers Forster is Professor of Physical Climate Change and founding Director of the Priestley Centre for Climate Futures at the University of Leeds.

Today marks the 10th anniversary of the landmark Paris Agreement, which has become a key compass in policymaking over the past years, preventing us from reaching a world with 4°C of warming. Climate ambition and implementation must continue at the pace the Paris Agreement requires.

Ten years ago, governments adopted an agreement that was supposed to keep the global average temperature “well below” 2°C above pre-industrial times and pursue efforts to limit it to 1.5°C.

A decade later, 1.5°C is no longer a distant possibility but a lived reality.

UN accepts overshooting 1.5C warming limit – at least temporarily – is “inevitable”

The Paris Agreement is failing to meet its lowest temperature goal. Yet it has done something profound: it has steered the world away from 4°C of warming, towards a level closer to 2-something.

That is nowhere near safe, but it is not nothing.

As a climate scientist, I’ve seen the climate changing over the years. The influence humans exert on it is unequivocal. And it became clear that in a world that is shifting so rapidly, it’s key to provide decision-makers with frequent, robust updates on the state of the climate system. This is why, together with other colleagues, we created the Indicators of Global Climate Change (IGCC) initiative.

Hot seas and even hotter land bring dangerous impacts

Since 2023, we’ve been using IPCC methodologies to update key climate indicators that help us track how the climate is changing and how much of that is due to human influence. We found that global greenhouse gas emissions are at an all-time high, with around 53 billion tonnes of carbon dioxide (GtCO2) having been released into the atmosphere, much higher than the approximate 41 GtCO2 in 2014.

The planet is now around 1.4°C warmer than in the late 19th century, compared with roughly 0.4°C in 1990, the year I embarked on my PhD, and about 1°C in 2015.

Land temperatures increased by 1.79°C from 1850–1900 to 2015–2024 and ocean temperatures by 1.02°C over the same period. Among the negative consequences of a warmer ocean, there’s sea level rise, which impacts coastal areas and becomes very dangerous for human settlements in those areas.

Unnervingly, this is likely the most stable and safest climate we will know for the next hundred years or more, given the carbon dioxide levels already in the atmosphere.

Capital shifting to clean energy sources

Although not as fast as humanity requires, climate policies have moved forward. The most visible change is in the power system. In 2015, renewables and nuclear made up about 24% of global electricity generation; today, they account for just over 40%.

In most of the world, new wind and solar are now cheaper than new fossil power. The economic case is better than ever to transition. The investment, innovation and policy shifts triggered or accelerated by Paris have rerouted capital in the right directions.

Taking the UK as an example, the government passed a net-zero emissions law in 2019, becoming the first major economy in the world to take such a step. The UK has also made significant progress in reducing emissions: in 2024, emissions levels were around 50% below those in 1990.

How the Paris pact can mature

Here’s what we need in the next 10 years for the Paris Agreement to survive its adolescence:

First, science cannot be treated as a battleground.

The latest IPCC cycle (AR6) had a more balanced authorship than ever before, with an approximately equal split between experts from the Global North and Global South and near parity between men and women. That diversity has strengthened, not weakened, the scientific consensus.

Yet at this year’s COP30 climate conference, some governments tried to sideline IPCC findings and to block routine updates on the state of the climate from the final decision text – not because the numbers were wrong, but because they were angry at the glacial progress on climate finance or did not want their own climate ambitions scrutinized too closely.

However, turning the scientific messenger into a target will not move a single dollar or tonne of CO2.

Second, the world needs to stop obsessing over the “net” in net zero.

The cheapest, fastest and most reliable way to slow the pace of climate change is to replace fossil fuels with renewables and, where appropriate, nuclear power, backed by storage, grids and efficiency.

Yes, we need to plan for carbon dioxide removal and yes, we need to help nature restore its damaged ecosystems. These “net” parts of net zero remain important, but without a planned phase-out of fossil fuel production and use, the Paris temperature goals are dead.

There are, however, glimmers of a post-fossil politics.

Charting a path away from fossil fuels

At COP30 in Belém, 24 countries, including major fossil fuel producers such as Australia and Colombia, backed language that points towards a managed transition away from fossil fuels.

And 18 nations have now endorsed the proposal for a Fossil Fuel Non-Proliferation Treaty, which would, in effect, do for coal, oil and gas what earlier treaties did for nuclear weapons: cap, then wind down, the most dangerous stocks.

Colombia seeks to speed up a “just” fossil fuel phase-out with first global conference

The Brazilian COP presidency is also working on a fossil fuel phase-out roadmap, signaling that the politics of “how” to leave fossil fuels behind is finally catching up with the science of “why”.

In some ways, it feels like 2014, when momentum built and delivered the Paris Agreement. The difference now is that we have the means to deliver on this vision.

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Why the Paris Agreement worked – and what it needs to do to survive