It seems like there might be a small typo in your question, and you might be asking how to "deduce" or understand global warming. If that's not the case, please provide more context so I can better assist you.

Assuming you're asking about understanding global warming, here are the key steps:

Learn the Basics: Start by understanding the basic science behind global warming. Know that it is primarily caused by the increase in greenhouse gases, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), in the Earth's atmosphere.
Review Scientific Studies: Read scientific studies and reports from reputable sources like the Intergovernmental Panel on Climate Change (IPCC) or NASA. These organizations compile research from scientists around the world.
Explore Climate Data: Examine climate data and trends. Look at temperature records, ice melt, sea level rise, and other indicators that scientists use to track changes in the climate.
Understand Human Activities: Recognize the role of human activities in contributing to global warming. Activities such as burning fossil fuels, deforestation, and industrial processes release significant amounts of greenhouse gases into the atmosphere.
Evaluate Impacts: Consider the impacts of global warming on the environment, ecosystems, and human societies. This includes more frequent and severe weather events, rising sea levels, disruptions to agriculture, and threats to biodiversity.
Assess Mitigation Strategies: Explore strategies to mitigate global warming. This includes reducing carbon emissions, transitioning to renewable energy sources, promoting energy efficiency, and protecting and restoring ecosystems.
Stay Informed: Keep up with the latest scientific research and news related to climate change. Understanding the evolving understanding of global warming will help you stay informed about new developments and potential solutions.
Remember, global warming is a complex and multifaceted issue, so a comprehensive understanding involves knowledge from various scientific disciplines, including climate science, atmospheric science, biology, and more.