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expert reaction to Copernicus 2023 Global Climate Highlights

Scientists react to the Copernicus 2023 Global Climate Highlights Report. 


Prof Richard Betts, Head of Climate Impacts Research, Met Office Hadley Centre, Met Office, said:

“Last year’s record temperatures are a reminder of how fast we are heating the planet by building up greenhouse gases in the atmosphere from fossil fuel burning and deforestation. The natural effects of El Niño have temporarily added to the long-term warming from human impact, which is currently about 1.3°C, but even once El Niño has subsided, warming will continue until we bring global emissions to net zero. The Paris Agreement’s 1.5°C refers to long-term warming and we expect to reach that around 2030 even in scenarios with rapid emissions cuts, so unless something very surprising happens we are going to have to learn to adapt to a climate above 1.5°C global warming. But it is still vital to reduce emissions rapidly so we can minimize the extent to which we overshoot 1.5°C.”


Prof Amanda Maycock, Professor of Climate Dynamics at the University of Leeds, said:

“This is the icing on the cake that was already baked once the forecasts early last year correctly predicted a strong El Nino would develop. It should not come as a surprise to anyone. While some left COP28 with a sense of optimism, it is clear to me that the collective will to cut carbon emissions is not strong enough to avoid 1.5C, and sadly we will be seeing many more headlines like this for years to come.”


Dr Friederike Otto, Senior Lecturer in Climate Science at the Grantham Institute – Climate Change and the Environment, Imperial College London, said:

“Climate scientists are not surprised about 2023 being the hottest year on record.

“The world did not reduce planet-heating emissions from fossil fuels and as long as emissions continue, temperatures will continue to rise. El Nino, a natural climate phenomenon, also contributed additional warming in the second half of the year.

“The hot year led to many severe weather events with disastrous consequences, especially for those most vulnerable in our societies. It also shows that comparable small changes in global temperatures have huge impacts on people and ecosystems.  Every tenth of a degree matters. Aiming to keep warming to 1.5 °C is more important than ever. But even if we end up a

t 1.6 °C instead, it will be so much better than giving up and not trying and ending up close to 3°C which is where current policies would bring us to.”


Prof John Marsham, Professor of Atmospheric Science at the University of Leeds, said:

“That 2023 is the hottest on record, is, sadly, not a surprise, but that doesn’t make it any less serious. 2023 saw some incredible extremes, with the impacts of climate change becoming ever more obvious: not only floods, fires, droughts and deadly heatwaves, but crop losses, food price rises and damage to nature – for example the mass loss of penguin chicks in Antarctica.

“We desperately need to rapidly cut fossil fuel use and reach net-zero to preserve the liveable climate that we all depend on. The good news is not only do the public support more action on climate, but that it is often win-win, e.g. UK renewables are both cheap and improve energy security. People are also now increasingly aware of the need to address the powerful vested interests who are trying to block the progress we all so urgently need.”


Prof Ilan Kelman, Professor of Disasters and Health, Institute for Risk and Disaster Reduction (IRDR), University College London (UCL), said:

“The data and analysis presented are exactly in line with long-standing expectations of a heating planet from human-caused climate change. We know that previous heatwaves were bad and, sadly, we now await much worse ones. These reported year-to-year trends display many factors other than human-caused climate change, while fitting exactly the general direction of heat that has long been warned about due to us changing the planet. We have the science. Let’s use it for action to help everyone.”


Prof Ed Hawkins, Professor of climate science, University of Reading, said:

“The record warm global temperatures and devastating extreme weather events of 2023 are a warning that such events will continue to get worse until we transition away from fossil fuels and reach net-zero emissions. A warning that we will continue to suffer the consequences of our inactions today for generations. A warning that we will regret not acting faster when the technologies to reduce emissions are so readily available.”


Prof Sir Brian Hoskins, Chair of the Grantham Institute, Imperial College London, said:

“2023 has given us a taste of the climate extremes that occur near the Paris targets. It should shake the complacency displayed in the actions by most governments around the world.”


Dr Leslie Mabon, Lecturer in Environmental Systems, The Open University, said:

“The data, whilst stark, is not surprising and reflects what the science has predicted for many years. The Copernicus data shows that we are already seeing the effects of climate change at a global scale. This is most notable in the record air temperatures that have been observed, but also in the high ocean surface temperatures and low sea ice levels that are reported.

“The report is also clear that whilst factors like El Nino contribute to some of the ocean surface temperatures, the overriding factor driving the changes is the concentration of greenhouse gases. The purpose of the Copernicus data is primarily to report what has been observed and not to explain causes or apportion blame, but we already know very well that this increased concentration of greenhouse gases is largely due to human activity.

“Data like that provided by Copernicus is an invaluable and constant reminder that there simply isn’t time to wait when it comes to responding to climate change. This means eliminating emissions from burning fossil fuels for power, heat and transport, as well as tackling emissions associated with agriculture and land use. The high number of weather extremes in 2023 reported by Copernicus, especially wildfires, is also a warning that as well as reducing emissions, governments at all levels need to step up their efforts to adapt to the impacts of climate change we are already seeing.”


Dr Kevin Collins, Senior Lecturer Environment & Systems at the Open University, said:

“Since it is the awards season, with this new data we might say that 2023 wins the OSCAR in the ‘Climate Changing’ category for hottest year globally since records began.  It has set new standards for air temperature, sea temperatures, carbon dioxide concentrations, loss of ice and a string of extreme events globally.  Notably, 2023 marks the first time on record that every day within a year has exceeded 1°C above the 1850-1900 pre-industrial level.

“The warming signal seen from these measurements is a key milestone on our unfolding climate changing path.  A one degree increase may not seem much, but these are global averages.  In some polar regions the increase may be 5 degrees more, accelerating the loss of ice cover and snow melt, with regional impacts on soils, rivers and seas.

“While the Copernicus data helps us understand changing temperatures, it is equally important to pay equal our attention to understanding the wider implications for our environment and humans.  As climate change influences every facet of our environment, so it impacts our water, food, health, energy, and transport systems and the overall quality of life in our built and rural environments.  These impacts will not be distributed equally in time or space: richer countries and communities will be able to mitigate some of the consequences as temperatures increase. Poorer communities living in marginal areas often have fewer options and are already experiencing significant changes to their livelihoods.  2023 may be a winner in its category, but this is a prize no-one wants to claim.”


Professor Chris Hilson, Director of the Centre for Climate and Justice at the University of Reading, said:

“Copernicus data has confirmed that 2023 was the warmest global year on record and that nearly half of the days were more than 1.5°C warmer than pre-industrial levels. Some of the anti-climate lobby may now be tempted to argue that we have breached the initial Paris Agreement temperature threshold and thus we should abandon efforts to mitigate and simply learn to live in a warmed world. This would be a great mistake. Not only is no such breach technically made out (which requires a longer timeframe and needs to strip out the additional warming effects of El Niño), but such an approach would produce a catastrophically unjust outcome. The current floods in the UK are a powerful illustration of how climate change produces very uneven impacts, exacerbating existing vulnerabilities. And in a warmer world, those working outside will, in many regions, face increasingly dangerous conditions.

“While these climate inequalities are real and pressing, the reality is that climate change is ultimately also the great leveller. The wealthy may think that they can shield themselves from a warmer world. But climate breakdown can easily lead to wider systemic breakdowns, including in food systems. At that point there is nowhere to hide. We should therefore avoid the temptation to shrug off these temperatures as the new normal. We can adapt to some things. However, the higher that temperatures rise, so adaptation becomes increasingly difficult, costly and inequitable.”


Dr George Adamson, Reader in Climate and Society at King’s College London, said:

“2023 had the highest global average temperature ever recorded, largely due to a significant transfer of heat from the oceans to the atmosphere.

“Whilst the degree of warming last year was higher than projected this should not come as a surprise: global temperature will continue to get warmer – within the noise of natural variability – as long as greenhouse gas concentrations continue to rise.

“The most significant number here is therefore the unprecedented greenhouse gas concentrations. We should focus on reducing this number, rather than the records that may or may not be broken in a particular year.”


Dr Nick Dunstone, Met Office Climate Scientist, said:

“The extraordinary global heat through 2023 made it possible to signal it would be the hottest year on record well before the year had finished. This level of warming is in line with climate projections.

“We expect the strong El Nino in the Pacific to impact the global temperature through 2024. For this reason we are forecasting 2024 to be another record breaking year, with the possibility of temporarily exceeding 1.5 °C for the first time.

“It’s important to recognise that a temporary exceedance of 1.5 °C won’t mean a breach of the Paris Agreement. But our forecast highlights just how quickly we are approaching this and hence we must expect further unprecedented regional climate effects.”


Prof Bill Collins, Professor of Climate Processes at the University of Reading, said:

“It is a shock that that this year has unarguably smashed the global temperature record. There is no opportunity here to quibble about hundredths of a degree, exceeding the previous record by 0.17 degrees should be an alarm call to everyone. More global warming is expected to cause even wetter winters in the UK and yet more flooding. This warming is due to ever increasing greenhouse gases, which this report confirms have exceeded their own records again this year. While we are probably now too late to prevent temperature rises reaching 1.5 degrees, deep, rapid and sustained reductions in emissions of carbon dioxide and methane are essential to bring down temperatures below the most dangerous levels.”


Prof Daniela Schmidt, Professor of Earth Sciences, University of Bristol, said:

“Reporting on the hottest year on record will become more and more common. The question is will this lead to action and large scale changes in behaviour? Every little change now, reducing every increment of warming, is important, while too often ambitions of change are promised by 2050, in another generation.

“Reducing the impacts to temperature alone does not paint the full picture. Increasing temperatures will result in changes to our rainfall, drought in some regions and some times, and floods in others. Many of the impacts of floods, droughts and heat will not be seen right indicating the long term impacts on us and our ecosystems.”


Dr Matt Patterson, Postdoctoral researcher in atmospheric physics, University of Oxford, said:

“The El Nino event in the tropical Pacific and unusually warm North Atlantic Ocean temperatures likely gave global temperatures a boost in 2023. However, increased greenhouse gas concentration in the atmosphere, caused by burning of fossil fuels, is by far the primary driver of this record heat.

“The record 2023 temperatures underline the rapidly shrinking window of time to reduce carbon dioxide emissions and keep global temperatures below 1.5C. Every tenth of a degree of warming ratchets up the climate risk with more heatwaves and extreme events. Devastating flooding events, such as that seen in the wake of Storm Henk, will become more common in a warmer world as a warmer atmosphere can hold more moisture.

“Our society must act urgently to transition away from fossil fuels towards cleaner energy to avoid dangerous warming levels.”



The Copernicus 2023 Global Climate Highlights report was published by Copernicus at 12:00 UK TIME on Tuesday 9 January 2024.



Declared interests

Prof Daniela Schmidt: No competing interests.

Prof Bill Collins: No conflicts.

Dr Matt Patterson: Dr Matt Patterson receives funding from the Natural Environment Research Council.

Dr Nick Dunstone: no interests to declare.

Prof Ilan Kelman: No interests to declare.

Prof Sir Brian Hoskins: No conflict.

Dr Leslie Mabon: No interests to declare.

Dr Kevin Collins: No interests to declare.

Dr George Adamson: no conflict of interest to declare.

Prof John Marsham: declares no conflicts of interest.

For all other experts, no reply to our request for DOIs was received.

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