Are there other environmental effects, positive or negative? Does it clean the air? Does it create water? Is it overall positive, neutral or negative in regard to its effect on the environment.
It’s responsible for adding a huge amount of nitrogen to soil, which fertilizes plants.
Lightning is powerful enough to break the triple bonds of N2 molecule in the atmosphere, producing nitrates. These NOx molecules (helped often by rain) then enter the soil where they become a fertilizer for plants. (Ninja’d)
Lightning also produces ozone (O3) which in low quantities is sometimes sensed as a “clean” smell by people but doesn’t do a whole lot of of good and is more of a pollutant.
Lightning creates a significant amount of air pollution in the US: it’s responsible for 5% of the NOx emissions there annually and 14% in July (when one assumes lightining strikes are at their peak. Lightning also creates a lot of ozone, which is a pollutant at low altitude and beneficial at high altitude (because it blocks UV radiation at high altitude. Here’s a cite:
https://www.nasa.gov/centers/goddard/news/topstory/2003/0312pollution.html
It’s a little depressing that a NASA article uses the misspelling “lightening,” but everyone makes mistakes.
Lightning stimulates mushroom growth, for poorly-understood reasons.
Well, when you lighten things, it means you use less material, which often means less pollutants are released to the environment during manufacturing. 
It probably keeps giraffe populations down but ive got no cites
Lots of people mistake the smell of petrichor for the smell of ozone. I’ve spent time with a TIG (arc) welder, which produces ozone for the same reason that lightning does. I don’t think I’d call ozone a clean-smelling gas…I find it mildly (and pleasantly) acrid.
I’m not saying you got it wrong, FTG. I just wouldn’t have described ozone as “clean-smelling.”
It’s definitely awful smelling in high enough amounts. But I’ve spent enough time in the desert to know “that smell” can’t be caused by rain hitting the ground when there’s lightning but no rain or the rain evaporates before hitting the ground.
I now live in a humid area with lots of thunderstorms (including one today). The “wet ground” smell after a storm is quite common and is unlike the ozone smell described above. Really quite different.
Note the info on the history of ozone on Wikipedia.
Giraffe struck by lightening:
Well, there are conifers whose cones rely on lightning-started fires to release their seeds. Certain coniferous forest floor flora and fauna also depend on occasional fires.
As of date, Science does not fully understand the mechanisms of lightning. Nevertheless, there is good evidence for NOx and Ozone as pointed above.
It fuzzes sand to form fulgurite and lecheltalierite.
Huh?
The comment that we don’t have a clear understanding of the mechanisms of lightning is correct.
It’s how the Earth gets charged… seriously. Google that.
Google what?
that
Lightning extracts minerals from rocks which at one point in time was an important step for the beginnings of life.