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The world’s leading climate scientists came together at the end of October at the once-in-a-decade Open Science Conference of the World Climate Research Programme (WCRP) in Kigali, Rwanda. Among NESP Climate Systems Hub researchers taking part were Dr Dewi Kirono on the ground and Dr Simon Marsland remotely. The Kigali Declaration or conference statement will be submitted to COP28 in December in Dubai. We spoke to Dewi and Simon to get their insights on how far we’ve come, where are we now and what is the future for climate science.

The WCRP Open Science Conference is only held once a decade. What are some of the biggest changes in climate science in the last 10 years?

Simon Marsland

The conference was a great forum to explore the many advances in climate science in the last decade. The global policy framework has also advanced, with the Paris Agreement being a key factor. The pointy end of climate extremes has been a surprise in how soon and how great the impacts have been, and 2023 has seen a lot.

Back in 2011 a central theme was around climate science serving society, and the climate services space has taken huge strides since. Now the focus is moving to the role of climate science in a broader context of societal issues: geopolitical instability; less than desirable progress towards the UN Sustainable Development Goals; inequality and the plight of the Global South, including Indigenous peoples; and widespread environmental degradation. There is a clear call for climate science to find its relevance in this broader context.

Dewi Kirono

Advancements in climate science in the last decade have largely been possible thanks to community effort in improving earth observations and open data access provision such as those by Copernicus. For instance, the analysis of remote sensing products shows that the continental water cycle is non-stationary. Not only does it include trends but also shifts in typical frequencies and extremes.

Making methodology transparent and reproducible has become increasingly important as part of ensuring robustness of the science. Subsequently, well-coordinated assessment and communication of credible science, through the IPCC Assessment Report for example, have convinced society about the “problem” faced by the planet.

We’re now at a point where climate science has to inform the development and implementation of “solutions”. In doing so, we are mindful that the world’s context is also changing. There is other environmental degradation to consider, the world is so much more interconnected, there have been changes in what people value following the COVID19 pandemic, the rise of artificial intelligence, declining trust in science, and so on.

 

The conference provides a snapshot of climate science in 2023. What were some of the strongest insights into climate science today?

Simon Marsland

The year 2023 itself has seen a continual occurrence of extreme climate events. The record low Antarctic sea ice extent. Canada’s massive area of forest wildfire and the related carbon emissions. Flash flooding like that in Libya and its human toll. Extensive marine heat waves and record high ocean temperatures, just to name a few. It is likely to be our warmest year in the modern historical record.

Advances in high-performance computing and data continue to enable our modelling capability, and our understanding more generally. Alongside this is the growth in the climate science community and the sheer volume of scientific literature being produced. One thing that struck me was the increasing awareness of potential climate tipping-points, and the prominence being given to irreversible changes. Another was the role of the carbon cycle where there have been great improvements in our understanding of how carbon moves through the Earth System, largely facilitated by much better observational capabilities.

Dewi Kirono

From the sessions I attended, highlights included:

• Increasing effort in understanding the role of the ocean (not just the land) in the climate system, not only in terms of exchanges of energy, but also in terms of biogeochemistry
• We know more about the carbon cycle, and we have been able to almost close the global carbon budget with an imbalance of around 3% that was highlighted in a keynote given by Australian (NESP CS) scientist, Pep Canadell.
• There is a lack of attention from the climate research community to the changing water cycle and its consequences on human water resources. This is a complex multi-disciplinary issue which should be higher on our priority list.

What were some of the standout sessions at the conference?

Simon Marsland

The opening plenaries introduced the conference theme ‘Advancing Climate Science for a sustainable future’. The Deputy Secretary General of the United Nations noted their anticipation around the Kigali Declaration, the conference statement now in preparation for delivery to the forthcoming COP28. There was a strong emphasis on the Sustainable Development Goals and the triple-problem of climate change, biodiversity loss and environmental degradation. A lot was said about the Global South, where the strongest climate change impacts of loss and damage are being felt by those least responsible for greenhouse gas emissions, alongside the challenges of adaptation and mitigation.

I admit a personal bias as a co-chair of the session ‘Climate knowledge co-production in a decision and policy context’. A very engaged group of speakers and attendees explored the challenges of co-design and co-production of science aimed to fulfil the needs of policy makers, alongside noting the power of transdisciplinary science in meeting these needs. The important role of decision makers was highlighted, and the need for community champions to be engaged in bringing people’s focus to local climate adaptation solutions. It was pleasing to see that the hub’s approaches to co-design and coproduction of knowledge place us at the forefront of best practice.

Dewi Kirono

There were many interesting and thought-provoking sessions. A couple of examples:

The digital revolutions and how they have been and will be shaping climate science and climate services. There have been three revolutions. First, the quiet weather forecast revolution during 1980-2020, when the weather forecast ability steadily improved due to investment in weather prediction and model development using more observations and computers. Second, the digital revolution from around 2015 to present day that enables us advancing climate modelling to allow for a kilometre scale modelling, for example. However, this requires a lot of resources. And so, the machine learning revolution from 2022 to date offers some solution. Machine learning models have been shown to beat conventional models and deterministic predictions. But of course, many questions remain, can machine models extrapolate? How do they represent physical consistency, etc.

The value of Global Climate Models (GCMs)/Earth System Models (ESMs) in actionable climate information. The session discussed responses to the increasingly pressing demand of local-scale and/or decision-relevant climate information from the society on climate research. An example of response is the storyline approach which allows one to start from the user perspective and/or local knowledge rather than from the global scale.

Another example is related to the modelling approach. Historically, the climate research community focus on a “top-down” approach, which assumes that modelling the global scale is prerequisite in order to understand the local scale. There is an alternative “bottom up” modelling approach where the small-scale phenomena is explicitly simulated while the large-scale is parameterised. More importantly, there is a need for the research community to give more attention to the ethical dimension of the GCMs/ESMs, especially when models and/or their simulation data are used beyond the original design and purposes of those models.

What can we expect of climate science in the next decade?

Simon Marsland

Our understanding of the complicated interactions between the physical, chemical and biological components of the climate system will continue to grow, based upon our ever-expanding understanding of the underlying science. Meanwhile machine learning and artificial intelligence are suddenly here now and beginning to perform at or above our prior capability in some areas of weather and seasonal forecasting. This capability will continue to grow at pace. There is a clear need to better understand the underlying algorithms behind this new technology and relate them to our understanding of the physical world.

There is also a more humbling aspect as the science matures and finds its place in the policy and geopolitical context. While climate science has been around for decades, it traditionally attracted people interested in mathematics and sciences. These days a new category of people are being attracted to the field, ones that want to be agents of change towards a better future for humanity and the environment. Bringing such folk into the mix will help better address the many challenges that were mentioned above through a move to transdisciplinary approaches to science.

Dewi Kirono

The Kigali Declaration in coming weeks will provide a roadmap for future research priorities. Some of the highlights I noted were:

Regarding fundamental research and modelling:

• Fundamental research concerning the complex interactions between the ocean and atmospheric, extreme events in response to climate change, climate forcings and feedback, tipping points, etc.
• Going deeper into scenarios. Are they plausible? What are the bio geophysical constraints that we’re facing? What are the possibilities of getting surprises and how we are going to respond to those surprises? Can we assess the effects of mitigation and adaptation measures?
• Better understanding of the cycle of water, energy, carbon and other chemical components – beyond their physical realm because all those cycles are deeply linked to societal issues.
• Improvement of Earth System models, for example through improved representation of hydro-ecosystems and human intervention in the water cycle.
• Next generation of Earth System Modelling – hybrid between the physics plus machine learning, benefitting from advances in earth observations capability and impacts of modelling capability.

Applied research / activities:

• Research to support climate intervention, including the associated ethical issues.
• The effect of regional and local scale changes on the global problem, while also bringing the global climate problem closer to the attention of people at the regional/local level.
• Improving interface between climate research and climate services
• Consolidating and coordinating our observation and modelling capabilities aligns with the digital and machine learning revolution.

What are the key international research priorities relevant to Australia?

Simon Marsland

Some old favourites will remain, such as research around the cycles of water, carbon and heat in a changing climate. Both modelling and observations require continued investment. Australia regards itself a land of extremes and improved understanding of climate change on extreme events will continue to be a priority. Heatwaves both terrestrial and marine affect human and environmental health, and the intersection between climate change and human health must be a priority.

Dewi Kirono

There are many and I have already mentioned a few. If I can highlight some from a session I co-convened on the Water Cycle.

Firstly, research priorities must include understanding the changing water cycle and its consequences on human water resources. Secondly, the observed trends in the water cycle in some regions has been attributed to climate driver. But in most cases these changes are attributed to other human-induced factors like urbanization or water abstractions. We need to consider methods to differentiate between the impact of climate change and the human-influences in the observed indicators of the continental water cycle, including extremes. Finally, we need to understand how water is valued (in a monetary as well as regulatory sense) by society. This is important because the link between weather-related renewable water resources, and the way they are managed, is driven by economic considerations and processes.