A synthesis essay thesis is an essay that combines information from multiple sources to form a single, unified argument. It is important to have a well-crafted synthesis essay thesis because it serves as the foundation of your essay. A strong thesis will be clear, concise, and provide a strong argument that the reader can easily understand.

A good example of a synthesis essay thesis could be: "Global warming is an important issue that should be addressed by governments around the world. To reduce emissions and mitigate the impacts of climate change, governments should focus on promoting green energy sources, such as solar and wind power, and reducing reliance on fossil fuels."

This thesis clearly states the main argument of the essay--that government action is needed to reduce the impacts of global warming--and gives a specific suggestion of how to do this. It is concise, yet provides enough detail to give the reader an idea of what the essay will focus on.

The rest of the essay then needs to provide evidence to support this thesis. This could involve researching current policies related to renewable energy and their impact on emissions, discussing potential impacts of climate change on ecosystems, human populations, and economies, and exploring potential solutions to reduce reliance on fossil fuels and increase use of green energy sources.

Overall, a strong synthesis essay thesis should be concise, provide a clear argument, and lay the groundwork for the evidence that will follow in the essay. The example provided here provides an example of how to craft an effective synthesis essay thesis.