Evolutionary adaptation to climate change

When the notion of climate change emerged over 200 years ago, few speculated as to the impact of rising atmospheric temperatures on biological life. Tens of decades later, research clearly demonstrates that the impact of climate change on life on Earth is enormous, ongoing, and with foreseen effects lasting well into the next century. Responses to climate change have been widely documented. However, the breadth of phenotypic traits involved with evolutionary adaptation to climate change remains unclear. In addition, it is difficult to identify the genetic and/or epigenetic bases of phenotypes adaptive to climate change, in part because it often is not clear whether this change is plastic, genetic, or some combination of the two. Adaptive responses to climate-driven selection also interact with other processes driving genetic changes in general, including demography as well as selection driven by other factors. In this Special Issue, we explore the factors that will impact the overall outcome of climate change adaptation. Our contributions explain that traits involved in climate change adaptation include not only classic phenomena, such as range shifts and environmentally dependent sex determination, but also often overlooked phenomena such as social and sexual conflicts and the expression of stress hormones. We learn how climate-driven selection can be mediated via both natural and sexual selection, effectively influencing key fitness-related traits such as offspring growth and fertility as well as evolutionary potential. Finally, we explore the limits and opportunities for predicting adaptive responses to climate change. This contribution forms the basis of 10 actions that we believe will improve predictions of when and how organisms may adapt genetically to climate change. We anticipate that this Special Issue will inform novel investigations into how the effects of climate change unfold from phenotypes to genotypes, particularly as methodologies increasingly allow researchers to study selection in field experiments. What are the major factors driving evolutionary adaptation to climate change? How can we harness this understanding to better predict how populations can adapt to a rapidly changing climate? The urgency of answering these questions is critical as more than a million species are currently directly facing the risk of extinction due to climate-driven environmental change. This puts research exploring processes and mechanisms that affect evolutionary rescue at the core of mounting a global response to the current climate crisis. Here, we highlight key contributions that collectively demonstrate the breadth of evolutionary responses that organisms exhibit in response to climate change, including classic responses (e.g., range shifts, plasticity, and evolutionary responses), but also less conspicuous phenomena such as social and sexual conflicts. Some contributions go right to the heart of understanding the genetic and epigenetic bases of the observed responses, ultimately linking the environmental effects to the genotype-phenotype map. Other contributions investigate the interplay between different types of selection with climate-driven selection in facilitating or hindering evolutionary adaptation, a major uncertainty that has been the focus of evolutionary research for a long time. These are pressing issues that require a deep understanding of processes that determine our ability to predict evolutionary outcomes of ongoing climate change. The final contribution of the Special Issue therefore explores the limits and opportunities for predicting adaptive responses to climate change. It builds on all the contributions of the Special Issue, and the viewpoints of many of their authors, to provide a road map for how we might be able to improve predictions with our current knowledge and what might be possible to predict in the future. We anticipate that this Special Issue will ignite investigations of how the effects of climate change unfold from phenotypes to genotypes and the selective forces that produce evolutionary rescue in response to climate change.