Climate and energy
In the 21st century, the earth's climate and its energy policy interact and their relationship is studied and governed by a variety of national and international institutions. The relationships between energy-resource depletion, climate change, health resources and the environment, and the effects that they have on each other, have been subject to numerous scientific studies and research efforts. As a result, a majority of governments see climate and energy as two of the most important policy goals of the twenty first century. The correlation between climate and energy rests on known causal relationships between human  population growth, rising energy consumption and land use and the resulting greenhouse gas emissions and climate change. The concern for climate change control and mitigation has consequently spurred policy makers and scientists to treat energy use and global climate as an inextricable nexus with effects also going in reverse direction and create various initiatives, institutions and think tanks for a high-level treatment of the relationships: