It's challenging to speculate on hypothetical scenarios with such long timescales, as they involve a vast number of variables and uncertainties. However, let's explore some general considerations:
Evolution and Adaptation: Throughout history, life on Earth, including humans, has demonstrated a remarkable ability to adapt to changing environments and challenges. If humans knew from the start that they might face potential extinction in the distant future, it could influence their behavior and decision-making, leading to a greater focus on long-term survival and sustainability. This might drive technological advancements, space exploration, and efforts to mitigate existential risks.
Technological Advancements: Over time, human civilization has consistently advanced in various fields, including science, technology, and medicine. With the awareness of a potential existential threat in the distant future, it's possible that human innovation and problem-solving capabilities would be further amplified, increasing the chances of survival.
Colonization of Other Planets: Knowing the potential limitations of Earth's habitability, humans might direct their efforts towards space exploration and the colonization of other planets or celestial bodies. This could serve as a strategy to ensure the long-term survival of the human species.
Cultural and Ethical Factors: The awareness of limited timescales could also influence human culture and ethics, leading to a greater emphasis on cooperation, environmental stewardship, and the long-term preservation of knowledge and resources.
Existential Risks: While humans might become more proactive in mitigating known threats, they could also face unknown and unpredictable existential risks. The challenge of ensuring survival for such extreme timescales could be beyond human capabilities.
Speciation: Over extremely long timescales, the human species might undergo further evolutionary changes, possibly leading to the emergence of new species, branching off from the Homo sapiens lineage.
It's important to note that predicting human behavior and the future of our species over billions of years is highly speculative and subject to numerous unknowns. Additionally, the existence of humanity or any species for such extended periods is influenced by factors like geological events, cosmic events, and the broader evolution of the universe.
As we currently stand, our understanding of the universe and our potential for long-term survival is limited. However, the pursuit of knowledge, cooperation, and a responsible approach to technological advancement may play significant roles in shaping our future.