Unraveling Climate Change: Episode 4 – Navigating the Landscape of Uncertainty

Welcome, readers! Today, let’s dive into how the IPCC evaluates climate change research globally. The process might sound complex, but we can break it down using the Rumsfeld matrix.

Back in 2002, Donald Rumsfeld, then U.S. Secretary of Defense, talked about “known knowns,” “unknown knowns,” “known unknowns,” and “unknown unknowns” in response to questions about intelligence. This framework helps us understand climate science too. Essentially, it guides us from what we don’t know and don’t understand (unknown unknowns) to what we know and comprehend (known knowns).

The IPCC, which has been analyzing climate data for over thirty years, uses a refined process that factors in “confidence” and “likelihood.” Confidence reflects the quality and consistency of evidence. The level of confidence is rated as very low, low, medium, high, or very high. For instance, a statement might be labeled as “medium confidence.” This means there is a reasonable amount of evidence supporting it.

In terms of likelihood, this evaluates how probable a certain outcome is. Here are the terms used:

• Virtually certain (99–100% chance)
• Very likely (90–100%)
• Likely (66–100%)
• About as likely as not (33–66%)
• Unlikely (0–33%)
• Very unlikely (0–10%)
• Exceptionally unlikely (0–1%)

Some recent data highlights the relationship between economic growth and CO2 emissions. Research indicates that globally, GDP per capita and population growth have been the biggest contributors to CO2 emissions from fossil fuels in the last decade, with *high confidence* in this assessment (IPCC AR6 WGIII Technical Summary).

Looking at future sea-level rise provides more insight. While projections suggest a significant possibility of exceeding current estimates, uncertainties remain—especially around Greenland and Antarctic ice sheets. Some experts have even warned that future sea-level rise could be greater than currently anticipated, possibly measured in meters over centuries (source). This highlights a complex interplay of known unknowns and unknown unknowns.

As we engage in this critical conversation, let’s recognize those working towards climate action. Local groups like the Australian Religious Response to Climate Change have initiated efforts to spotlight climate issues in elections (read more).

As we reflect on impactful voices for our environment, we remember Pope Francis, who recently passed away. He urged leaders to prioritize the environment and address climate change. His words are a reminder of the disparities in pollution responsibility: wealthier nations contribute significantly more to environmental degradation while poorer populations bear the brunt of its effects. Francis criticized short-term gains that hinder progress and called for policies harnessing nature’s regenerative capabilities to fight climate change and biodiversity loss.

In summary, the IPCC’s methods allow us to better understand our climate challenges through structured assessments. As we strive for clarity in an uncertain world, let’s continue to listen to advocates and work together for a sustainable future.

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