• To understand sea level and ice sheet stability in a warm world.
• To understand how water cycles will operate in a warm world.
• To understand abrupt transitions across tipping points into a warmer world.
• To understand ecosystem thresholds and resilience in a warming world.
STRATEGIES AND TOOLS TO IMPLEMENT THE RESEARCH AGENDA
Implementing the deep-time paleoclimate research agenda described above will require four key infrastructure and analytical elements:
• Development of additional and improved estimates of precipitation, seasonality, aridity, and soil productivity in the geological past.
• Continental and ocean drilling transects to collect high-resolution records of past climate events and transitions, to determine climate parameters before and after these events, and to model the dynamic processes causing these transitions.
• Paleoclimate modeling focusing on past warm worlds and extreme and/or abrupt climate events, at high resolution to capture regional paleoclimate variability. Model outputs will be compared with climate records from drilling transects and fine-tuned.
• A transition from single-researcher or small-group research efforts to a much broader-based interdisciplinary collaboration of observation-based scientists with climate modelers for team-based studies of important paleoclimate events.
ENCOURAGING A BROADER COMMUNITY UNDERSTANDING OF CLIMATES IN DEEP TIME
The public—and indeed many scientists—have minimal appreciation of the value of understanding deep-time climate history and appear largely unaware of the relevance of far distant past times for Earth’s future. The paleoclimate record contains surprising facts—there have been times when the poles were forested rather than being icebound; there were times when the polar seas were warm; there were times when tropical forests grew at midlatitudes; more of Earth history has been greenhouse than icehouse. Such straightforward concepts provide an opportunity to help disparate audiences understand that the Earth has archived its climate history and that this archive, while not fully understood, is perhaps science’s best tool to understand Earth’s climate future.