A steppingstone in climate-science progress

Darrell Kaufman

Darrell KaufmanBy Darrell Kaufman
Regents’ Professor
School of Earth Sciences and Environmental Sustainability

Like a long-awaited sequel to a riveting story, the Intergovernmental Panel on Climate Change will release Vol. 1 of its fifth assessment report next Friday. This major international production summarizes the current understanding of the scientific basis of climate change. It’s the latest incremental step in the evolution of the burgeoning and dynamic field of climate science—one that NAU researchers have helped advance.

The report is bound to attract major media attention. It features predictions about the future of our planet. It weighs the proportion of recent climate change attributed to human causes and increases the level of scientific certainty that burning fossil fuels impacts global climate. This topic will no doubt draw fire, especially against the backdrop of President Obama’s recently announced Climate Action Plan.

Some media outlets likely will contrast the increased certainty of human-influenced climate change with reports of how much the computerized climate models that were used in previous studies may have over-predicted the actual warming during the last 10 years, which were nevertheless the warmest 10 years on record.

Multiple lines of evidence and reasoning have been brought to bear on our understanding of Earth’s climate, and many are independent of predictions by computer models. For instance, evidence from Earth’s own natural archives attest to conditions in its not-so-distant past. The evidence is clear: temperature and greenhouse-gas content of the atmosphere are strongly coupled; sea level and global temperature go hand-in-hand.

With the release of the Intergovernmental Panel on Climate Change report, attention will rightfully focus on the revisions since the last major assessment in 2007. To some, this will suggest an uncertain science. While it’s true that refinements are made and uncertainties are exposed at the frontiers of science, the latest progress report builds on an already broad and sturdy foundation of scientific knowledge. Like other scientific endeavors, our understanding of Earth’s climate system is improved as our appreciation for the limits of our knowledge grows.

Editor’s note: The Intergovernmental Panel on Climate Change’s new report includes the results of published investigations by NAU scientists, including Darrell Kaufman, Bruce Hungate, Nick McKay and Christopher Schwalm.