Why would you think the Earth and animals would be fine? They are just as susceptible to radiation as we are, and they don't have the option of getting Chemo or surgery when they get cancer.
If every living thing on the planet dies, there will be no more Mother Gaia. If she was going to kill us off to protect herself, she waited too long.
There has already been an ELE level of Uranium, Plutonium, and over 600 other radioactive isotopes blown into the upper atmosphere from the explosions of reactor #1, #3 and it's MOX fuel, and #4. Some fuel rods were found fired like artillery shells up to 15 miles from the plant by #3.
We currently have no technology to recover the material still in the upper atmosphere, nor to recover the radioactive fallout.
There has already been an ELE level of radioactive isotopes released into the ocean. One result of the initial material blown into the sea and the emergency cooling with sea water was the formation of over 3000 radioactive isotopes as well as never-before seen uranium and plutonium buckyballs.
These little bubbles of uranium or plutonium are very light and they float along the surface of the ocean with the sea foam until they reach land. The structure of buckyballs keeps them from falling apart once they blow onto land, sea mist can carry them hundreds of miles inland.
We currently have no technology to remove all of the radioactive isotopes that have been released into the ocean. Please note that as many hundreds of tons of highly radioactive water is released into the ocean EVERY DAY this is only getting worse.
There has already been an ELE level event with three nuclear cores melting down into corium and burning their way into the ground. The ongoing releases of radioactive iodine and radioactive xenon show that there is still active fission going on. This adds to the total atmospheric and oceanic releases. As the corium continues to migrate underground it will contaminate the drinking water for the whole island since it is a shared aquifer.
We currently have no technology to recover these corium blobs, now that they have burned through containment.
ELE #4 - In progress
Should a fuel rod break while pulling it from the tangled mess, the individual fuel pellets will fall to the bottom of the tank, where they will immediately begin to give off copious amounts of radioactive gas. They will stop work, seal the building, and vent the gas to the atmosphere. Once the gas level subsides, they will resume work. This will be repeated for however many fuel rods might break.
If a sufficient number (2?) of fuel pellets come to rest together at the bottom of the pool, they will begin to go critical, which will dramatically increase the temp of the water, and increase the radioactivity. If too many pellets come in contact, the criticality will boil the fuel pool dry, catch fire, and possibly explode. Should that happen, the whole site will have to be abandoned, and within weeks massive amounts of radiation would form a plume that would circle the globe.
The effect of each of the above is ever-increasing numbers of cancers, increases in miscarriages and birth defects, increases in strokes and heart attacks, increases in chronic digestive problems, and all the problems associated with the weakened immune system. Should scenario #4 play out people worldwide will get radiation sickness (hair loss, nose bleeds, vomiting, diarrhea, fatigue) and since uniquely, this radiation sickness won't decline, because unlike with a nuclear bomb, the radiation won't decrease over time, it will only increase.
What truly makes this an ELE is what will happen to the human genome. The slow destruction of the genome is inevitable with the level of radiation we're talking about, since whatever mutation we accumulate will be passed to our children, and eventually the number of mutations will result in a non-viable genome.
This will be happening to every living thing on the planet, by the way, not just humans. It's anybodies guess what it will be like to have all of nature going through this at the same time.
So slow, or fast, doom is already signed, sealed, and delivered. It's just a question of when we mark on our calendars that the world realizes it's fate.
Most of the above is drawn from information Tepco itself has released over the years, as well as MSM stories, I've just put it together in one place.