Desolate/Rejuvenate

You change the very landscape within 50 miles of your current location for the duration. You must be outdoors to cast this spell. Moving to a place where you are no longer in contact with the ground causes this spell to end early.

When you cast this spell, you change the current environment of the surrounding region, which is determined by the DM. You can make extreme changes, or minor ones, choosing from the following effects:

• Desolate Land. You make the land more arid. Water sources within or flowing into the area are dammed, diverted, or dry up as soil turns to sand and less-hardy plants wither under the heat of a newly strengthened sun. Precipitation drops dramatically, as natural cloud formations avoid the area entirely while the effects of the spell last. These changes can create a desert of a previously-verdant landscape. Any crops planted within the area for the next year yield one-quarter of their typical harvest.
• Verdant Expanse. You make the land more fertile. Water swells from below the ground or finds its way into the area from nearby rivers and streams, creating new lakes and waterways across the region. Plant life of your choice is sown and grows to fruit, attracting animals, and for one year all crops grown within the area become enriched, as per the Plant Growth spell. Precipitation increases to sustain your chosen environment, as natural cloud formations are attracted to the area while the effects of the spell last.
• Temperate Form. You adjust the overall environment and climate of the land to any degree, towards or away from either of the options above. You might make a swamp slightly drier, or add an occasional oasis to a desert, for example.

The chosen effects gradually take place during the casting of the spell. When the spell ends, the environment returns to normal over the course of the next 1d4 x 10 days. If you concentrate on the spell for its full duration, the effects are permanent until reversed by magic, such as the Wish spell, or another casting of this spell. Environments surrounding a region transformed by this spell may be indirectly impacted by the changes after a year or more has passed. However, the magic of the spell prevents sudden, catastrophic shifts to any adjacent areas.