"Ask the Expert" articles provide information and insights from MSU scientists, researchers and scholars about national and global issues, complex research and general-interest subjects based on their areas of academic expertise and study. They may feature historical information, background, research findings, or offer tips.

Yadu Pokhrel, associate professor in the Department of Civil and Environmental Engineering at Michigan State University, discusses what climate change is and how it is impacting the world. Pokhrel answers questions about the causes of climate change and what we can do to help.

What is climate change?

When we say climate change, it is basically change in temperatures or a rise in temperatures. Climate change also includes a lot of things within the broader Earth's system, and water cycle is one of them. But when there's any change in the water cycle because of climate change, it means that we are changing the fundamental need for human beings on Earth and that includes water, direct water supplies for humans, food production, energy generation and so on.

What do these changes in temperature do to the planet?

With changing temperatures, basically what happens is the capacity of the air to hold moisture is going to increase. When that happens, the hydrological cycle gets intensified. And then the consequence is that there can be more rain in some places, and there can be less rain in other places.

What causes climate change?

In our recent study, we found significant increase in extreme to exceptional droughts and that was caused primarily by climate change due to increased greenhouse gas emissions. One of the most striking findings of the study was that under a medium to high rate of global warming, the number of people living under extreme exceptional droughts would more than double during the 21st century.

Humans directly contribute to climate change by putting more greenhouse gases into the atmosphere. That causes change in temperature and impacts the water cycle. But there is also another aspect of human activities related to drought, which is water management on land like building dams or pumping groundwater for irrigation. And by doing that, humans are also directly altering the water cycle on land. When these two activities are combined, the impacts can be even greater.

How have we seen climate change affect communities thus far?

Just to take some examples. Cape Town in South Africa went through a severe drought in 2018, and California is right now in a decade of drought. And with climate change things are going to get even worse, and we may see more places like these in the future. More intense droughts are happening everywhere. So, the issue related to drought is not just a local problem — in some places it's a global problem.

What can we do to help?

Climate change is going to continue even if we start limiting greenhouse gas emissions significantly right now. So, it is critical that we increasingly consider climate change issues in teaching and produce the next generation of scientists and engineers who can deal with the increasing impacts of climate change.