Past as Prologue: What Do Recent Climate Trends Tell Us about Tomorrow?

Barring a volcanic cataclysm, it is virtually certain that global temperatures will rise over the 21st century. There remains a good deal of uncertainty over how much of a rise to expect by 2100, mainly because it is still unclear how quickly or slowly the world’s economies will act to restrict carbon emissions. It has also become increasingly clear that the rise in global temperature will not be linear: the last few decades reveal a “two steps forward, one step back” pattern, largely driven by multidecadal patterns of ocean circulation. A good deal of uncertainty also remains in how climate change will play out on the local and regional scale, with the projected trends in some locations more confidently identified than in other locations. Despite these unresolved questions, many aspects of future climate change projected by models are extensions of phenomena already being observed, such as the exacerbation of drought impacts by rising temperatures and the tendency in much of the world for precipitation to be increasingly concentrated in heavier bursts. By understanding which recent trends in climate are likely to continue or intensify, we can gain more insight on the challenges that near-term climate change is likely to bring to horticultural and agricultural operations over the next several decades.