Benny Peiser: What Is Climate Realism?

Understanding Agreement & Disagreement in Climate Science

What is Climate Realism?

There are many scientific agreements and disagreements in climate science. While there is general agreement about the modern global warming trend (since 1850), scientific controversies increase as climate research moves further back in time, and predictions move further into the future. Climate realism acknowledges the significant difference between verifiable and replicable knowledge, and hypothetical knowledge based on indirect evidence.The lecture will attempt to address which knowledge claims are more reliable and trustworthy, and which are less so. What do we really know about terrestrial climate change, and what are our main knowledge gaps? Why do we accept certain scientific claims about climate change but are doubtful about others?This lecture is not about who is right and who is wrong.The key questions of my talk:

• Which knowledge claims are reliable and trustworthy and which are less so?
• What do we really know about terrestrial climate change?
• Why do we accept certain scientific claims about climate change but are doubtful about others?

What do we reliably know about terrestrial climate change?

RECENT & PRESENT: more robust knowledge based on empirical observations and verifiable temperature measurementsPAST: ambiguous knowledge based on circumstantial evidence and estimates of paleoclimate proxy dataFUTURE: Climate is a highly complex, chaotic and non-linear system; affected by numerous known & unknown factors, dynamics and feedback loops, i.e. long-term future climate cannot be predicted reliably.

Empirical vs theoretical knowledge

Empirical evidence - verifiable data and replicable methods.Reliable data and reliable estimates & predictions diminish the further one moves back or forward in time.Modern warming trend (since ~1850) generally agreed because observational data is fairly robust and based on verifiable measurements.Controversy increases as climate research moves further back in time and further into the future.Climate realism acknowledges significant difference between verifiable knowledge and hypothetical knowledge based on indirect evidence.Full lecture