b'35Carnegies Yoichi Shiga (left), Anna Michalak, Joe Berry (right), and colleagues conducted a study showing new carbon dioxide uptake patterns. Image courtesy Yoichi ShigaInverse modeling starts with the results (atmosphericThese results are the first instance of using a network CO 2variations) and then calculates the causes (CO 2 of CO 2observations to evaluate the utility of SIF in fluxes at the Earths surface). understanding space and time variability of carbon uptake at crucial regional to continental scales. They also found that SIF indicates a redistribution ofFurthermore, these results offer a new, powerful tool the North American land carbon sinks with increasedto probe the photosynthetic activity of plants and how CO 2uptake in croplands and decreased CO 2uptakeplants affect the atmosphere. in needleleaf forests during the growing season.'