ch 13: This chapter considers whether Homo sapiens is as “unstoppable” as the Titanic was “unsinkable.” Reviewing scientifically credible threats to our species’ long-term survival, this chapter shows that some threats looming large in the popular imagination are actually extremely unlikely to cause human extinction. Actual threats to long-term human survival, such as meteor impacts and large-scale volcanism, garner far less attention than they deserve and they share a similar solution.