The 10 ​Science ​‘Must​ Knows’ ​on ​Climate ​Change

It is undoubtedly a challenge for climate policy actors to identify reliable evidence to support sound decision-making processes for tackling climate issues effectively. Still, differentiating between fact and fiction, well-designed and invalid science, evidence- or interest-based arguments is precisely what determines the quality of climate policies.

While selecting trustworthy sources from a seemingly endless mass of information might seem an impossible task, one thing can and should be done: defining indisputable climate facts. A handful of climatic issues enjoy extensive testing and research, and their conclusions are as reliable as it can be. Yet, decision-makers spend precious resources debating the verity of these climatic issues, resources that could be applied to furthering climate action.

In this short paper, the Earth League and Future Earth unravel 10 scientific facts on climate change that should be recognized by those pursuing the goals set by the Paris Agreement, while proposing policies to achieve them.

1. Evidence shows that Earth has entered a new geological epoch – the Anthropocene – with profound implications for humanity and the relative stability of the Earth system.
2. Earth is approaching tipping points due to human pressures.
3. Risks of extreme weather are increasing.
4. Rising sea levels and ocean acidification are growing threats.
5. The costs of climate change are already being felt today and will increase in the future.
6. Human health is at risk from air pollutants that alter the climate, and the impacts of a changing climate, which are decreasing food security and increasing the risks of disease and heat stress.
7. Climate change is likely to exacerbate the risk of large-scale migration and civil unrest.
8. The world needs to act faster: deeper cuts are needed to reduce risk of global average temperature rising 2 °C above pre-industrial levels. A pathway of halving global emissions every decade is consistent with this goal.
9. Analyses suggest that it is possible for the world to meet Paris Agreement targets if nation states cooperate and coordinate mitigation efforts. Carbon pricing is an important policy tool that would create substantial revenues amounting to potentially several percent of GDP.
10. Adaptation and resilience building are necessary even if the world succeeds with aggressive international action to reduce emissions of greenhouse gases.