Green infrastructure systems naturally hold and retain stormwater. Examples include rain barrels, a row of trees along the neutral ground, or replacing impermeable surfaces with greenspace or permeable materials. These strategies not only aid climate change adaptation, but also can contribute to greenhouse gas emissions reductions. Increasing the number of healthy, long-living trees in the city can help reduce our net greenhouse gas emissions. Green infrastructure reduces storm runoff by retaining water, reducing the amount that must be pumped out of the city and decreasing related energy use.