Emerging Threats in a Rapidly Changing World

The Earth’s environment is changing. Since the Industrial Revolution gases have been building up in the atmosphere, trapping heat and raising the temperature of the planet. Warming soil and increased mortality rates in plants and animals elevate the activity of microbiota, amplifying the emissions of CO2 and other greenhouse gases. Secondary biological consequences—including new patterns of phenology, the spread of disease and invasive species, disrupted food webs, and many of the threats described in the previous chapter— interact in ways that make conservation much more challenging. For example, drought-stressed trees in boreal forests are more susceptible to the pests and disease that thrive in the altered climate, and the dead trees provide tinder for wildfires, which are also increasing in spread and intensity because of climate changes. Other species may react to the loss of mature forest habitat, disrupting trophic relationships (Parmesan and Yohe 2003). Global changes in climate, sea levels, and ocean chemistry are well documented. Although there is uncertainty about the magnitude of future changes, there is scientific consensus that the trends we see now will continue for multiple human generations. Scientists expect more species to become threatened or endangered and the rate of extinction to increase (Thomas 2012; IPBES 2019). Climate change and its secondary biological consequences affect people and their