We have been funded by the National Science Foundation to study interactions between the North American Monsoon climate system and the ecology of ecosystems in the southwestern US. The North American Monsoon occurs every summer, and brings rain to arid regions, driving the growth of plants and activities of animals. We are studying the importance of this recurring climate system on the spread of invasive, summer-active grasses and connectivity among ecosystems with regard to the spread of wildfires. We are also creating new computer models to predict the timing and strength of the monsoon rains each year, the sensitivity of the monsoon system to cyclic and progressive changes in sea surface temperature in the Tropical Pacific and the potential for ecological changes on the Earth's surface to amplify or mute the intensity of the monsoon rains. A major emphasis of our studies will be to also discern the potential for future warming in the climate system to cause changes in the timing and intensity of monsoon rains.