Human-caused climate change has resulted in widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere. The year 2023 was the warmest on record by a large margin, with widespread extreme weather. This trend continued in the first half of 2024.

Global greenhouse gas (GHG) emissions rose by 1.2% from 2021 to 2022, reaching 57.4 billion tons of carbon dioxide (CO2) equivalent. Globally averaged surface concentrations of CO2, methane (CH4) and nitrous oxide (N2O) also reached new highs.

Urgent mitigation action is needed, as is climate adaptation.

“We need urgent and ambitious action now to support sustainable development, climate action and disaster risk reduction. The decisions we make today could be the difference between a future breakdown or a breakthrough to a better world,” said WMO Secretary-General Celeste Saulo.

“Artificial Intelligence and machine learning have emerged as potentially transformative technologies that are revolutionizing weather forecasting and can make it faster, cheaper and more accessible. Cutting-edge satellite technologies and virtual realities that bridge the physical and digital worlds are opening new frontiers in, for instance, land and water management,” said Celeste Saulo.

“However, science and technology alone are not enough to address global challenges such as climate change and sustainable development alone. In an increasingly complex world, we must embrace diverse knowledge, experiences and perspectives to co-create solutions together,” she said.

United in Science is issued annually. It is a multi-organization compilation of the latest weather, climate, water and related environmental and social sciences for the future.

United in Science offers much-needed grounds for hope. It explores how advances in natural and social sciences, new technologies and innovation enhance our understanding of the Earth system and could be game changers for climate change adaptation, disaster risk reduction and sustainable development.

Key messages

• Multi-agency report highlights challenges and opportunities

• Summit of the Future decisions: a choice between breakthrough or breakdown

• Increasing climate change impacts reverse development gains

• Gap between aspiration and reality widens

• New technologies and innovation are potential game-changers

• Natural and social sciences are part of wider transdisciplinary approach

United in Science 2024 - Key Messages

Editor: HU Yichen