The visualization makes no sense. You can't go back or forward in time to check out a trend a little closer. It looks good on the surface but in my view it's totally useless to get real information.
I used it myself last year when I was wondering about the emissions associated with different diets (specifically I was curious about what was more effective from a reduction standpoint: being a vegetarian at different points of time vs. owning an electric car. Since the disposition of electricity has changed pretty significantly since the early 90s in some places it varied pretty widely [the informal lit review of food-based emissions was quite a mess though]).