Earth Day is here again to remind us that we’ve got a nice little planet to live on -- for now.

Environmental conservation in an age of climate change is tough. Here are just a few examples of the vast problems our planet faces and some efforts to mitigate those issues, as well as the new problems we might cause by trying to fix the first problems.

Problem: Too much greenhouse gas in the atmosphere, trapping heat underneath it like a blanket -- a climate-changing, world-altering blanket.

Possible solution: Little marine organisms called plankton love to chow down on carbon dioxide, but they need iron to grow. Some proponents of “geoengineering” think we could nudge plankton into a greenhouse gas feeding frenzy by scattering lots of iron in the oceans (sometimes called “seeding” or “ocean fertilization”).

Problem with the solution: The 2010 eruption of the Icelandic volcano Eyjafjallajokull provided an excellent opportunity to test the ocean-seeding theory. A recent paper in the journal Geophysical Research Letters offered an unhappy verdict: In a large area of ocean bombarded with volcanic ash, there was a short-term bloom in phytoplankton. But the extra iron caused the plankton to lose some of their innate supplies of nitrogen, another essential element for growth, so the momentary increase in plankton didn’t do much for clearing up greenhouse gases.

Problem: One of the consequences of excess carbon dioxide is that it makes the oceans more acidic, which is bad news for lots of marine life (especially shellfish, which will lose the raw materials to make their shells in a more acidic environment).

Possible solution: Another geo-engineering scheme involves dumping lots of quicklime -- a material produced when you heat limestone up to a very high temperature -- which makes the oceans more alkaline (the opposite of acidic). It also increases the ability of seawater to absorb carbon dioxide.

Problem with the solution: If that plan works, we would need a lot of limestone to have a measureable effect. Production of limestone would have to be majorly ramped up, and we would still need a ton of energy from fossil fuels or natural gas to heat the stone. It’s also unclear what the rippling effects of dumping a lot of quicklime into the sea might be.

“To start pouring many tons of calcium hydroxide into the oceans in an attempt to decrease the amount of CO2 in the atmosphere is akin to shoving a rod into your brain and hoping you come out the other side a happier person,” environmental blogger Hank Green wrote.

Problem: Many conservation models are built on the idea of isolated nature preserves. But nature tends to color outside the lines -- animals migrate and move through different territories, and climate change means many animals and plants may shift to new areas in the near future.

Possible solution: Create “conservation corridors” that connect a broad range of ecosystems. One such proposal is the Yellowstone to Yukon Conservation Initiative, which envisions linking up a large swath of land in the U.S. and Canada that would provide broad refuge for bears, birds, wolves and fish.

Problem with the solution: In this case, the problem is more about the feasibility of implementing the solution. Human encroachment on the wild is increasing with population growth, so conservationists will have to act fast before development slices through proposed corridors. The Rocky Mountain areas of Canada and the U.S. are likely to become prime real estate in the near future, thanks to oil and natural gas exploration and, possibly, a future wine industry made possible by climate change.