I've noticed that "city becoming overrun by weeds and wild animals" is a common trope of judgement in the Prophets: Isaiah 7:23-25, 13:21-22 and 34:11-15, Hosea 9:6, Zechariah 2:9-15 and probably other places I've missed. There's also a link here between this condition and spiritual dereliction - the Isaiah 13 example (in the NRSV) includes a reference to "goat demons" and the Isaiah 34 one has the sole mention of Lilith in the Bible.
How should Christians concerned for the environment read these passages? I know this isn't your speciality, but you're well-read on theology and I value your opinions so I want to hear what you have so say.
Ooh, thanks for the question! (And for valuing my opinion.) These topics themselves may not be my specialty, but Biblical interpretation is my bread and butter. And actually terraforming in Isaiah is one of my minor interests! As always, this came out...too long.
In short, I think that we should read these verses not as presenting a natural sort of wilderness, but an unnatural and chaotic space that occurs as the result of sin. Without looking at the verses or their context, my immediate thought was that it's not good to have cities become deserted and be taken over by wild animals. God creates a hospitable place for human life and this is the warning that that can be undone. These verses are really about demonstrating God's power over creation, and their context is more political than environmental. We can also compare this to images of redemption, where the land rejoices and blossoms and supports life. That's the real dichotomy in these images, is land bringing death or land giving life. These verses also aren't really about the environment, but I think it is possible to draw a fairly direct line to care for the environment here if you want to come on a longer journey with me.
Looking deeper, I always think the first task is to contextualize the verse. As you said, these are all messages of judgement. I'm going to look at Isaiah 34 most closely, because it's proximity to Isaiah 35 is really interesting. So we have 11-15, which describes pretty normal wilderness, for the most part. The animals that will live there are the hawks, hedgehogs, owls, ravens will live there, and there will be no people there, which at this point mostly just sounds like a place I'd like to visit. Then we get nettles, thorns, jackals, goat-demons and Lilith, which is less appealing.
As an aside, Lilith here should just be interpreted as some kind of demon or a foreign goddess, which is what she was at the time this was written. The idea of Lilith as the first wife of Adam comes much later in Jewish thought and isn't part of the tradition we share with Jews. I don't think Christians ought to consider ourselves as having access to that interpretation. As for "goat-demon," I've also seen that translated as wild goat; it seems to be one of the many words in this passage that we just aren't sure about, like "hedgehog." (Hawk, hedgehog, and owl here are actually all words we can't identify.) Lilith and the goat-demons are also just kind of malevolent creatures that ancient Israelites believed lived in the wilderness, so it's honestly still pretty typical wilderness.
Looking back though we can see that God isn't just "rewilding" Edom. (And if God were-- well, my feelings on the pitfalls of rewilding are for another post.) Earlier in 34, the mountains will flow with the blood of the slaughtered, the host of heaven will rot away, and the streams of Edom will be turned into pitch and the soil into sulfur. There's really no good word in English for these streams, which are wadis, and are only streams when there's heavy rain. (Readers in the American southwest may be familiar with arroyos, which are very similar. For you in England and me in Missouri, there's really no comparable natural feature.) For the wadis to dry up, we're talking about drought, and then fire, to get pitch and sulfur. But what we're really talking about is the judgement and power of God.
This isn't nature "healing" after humans leave, this is destruction, this is ruin, this is death. "There too the buzzards shall gather, each one with its mate" (34:15b). Isaiah is writing this (this is from First Isaiah, which is still attributed to Isaiah ben Amoz) in the devastation of the Assyrian captivity. It's not specifically about creation care or our failures thereof causing this. Victor Zinkuratire, one of the contributing writers to the Global Bible Commentary (2004), writes "This is poetic language and the desert might as well be a theological description of all the damage physico-ecological, social and spiritual that arrogant and greedy human beings cause. This is the kind of desert that many African countries are in today." So one answer to how do we read this for the environment is don't; read it about politics and warfare, and understand that it's not saying war will return the earth to some kind of nature preserve.
Ultimately, this passage is about judgement (and then hope, in Isaiah 35) in the face of geopolitical strife. Isaiah contains a lot of really direct political admonishments, down to criticizing treaties that nations drew to defend against Assyria that failed (Isaiah's verdict: You should have trusted God, not generals). Isaiah is not predicting climate change, and I want to make that clear.
With that said, I do think we can see pretty clear parallels to climate change in the text. Jumping out of Isaiah, back to Leviticus and Deuteronomy, the Israelites have pretty clear responsibilities to the land, which will "vomit" them out if they make it unclean (Lev 18:28, Deut 12:29). (This is of course related to the purity code, but obviously I'm not suggesting that homosexuality is what's going to cause this.) The ancient Israelite had a strong sense that sin corrupted the land (Num. 35:33-34, Isa 24:5-7, Ezek 22:24, Ezra 9:11 are all recommended by my study Bible as references here). I think Christians who are concerned for the environment need to really grasp that there is a way in which that is literally true and need to see the way that sin has real consequences.
The sin of greed is destroying the earth. We know that civilizational collapse is possible from climate change. We said really often in my Law and Narrative class that we are not punished for our sins, but we are punished by our sins. As an American, I can say that we've learned this again and again with ecological disasters that we've caused, like the Dustbowl and wild boars and devastating monocultures. BUT irresponsible agricultural practice and its consequences is really more Levitical than Isaian.
Anyway, one final thought is the transition into Isaiah 35. After all of this destruction, we turn to redemption and the very first words of redemption are "The wilderness and the dry land shall be glad, the desert shall rejoice and blossom; like the crocus it shall blossom abundantly, and rejoice with singing" (35:1). In redemption, both the land and humanity thrive. So when we see places overrun with wild animals as a message of judgement in scripture, we can think of that as something being out of balance, or the tension being off. Scripture does not affirm an anti-human environmentalism, we have a place in the world. I prefer to think of that place as stewardship rather than dominion, but even reading Genesis as giving us dominion over the earth, we have a responsibility to be the sort of just and merciful ruler that God is and not to take more than the land can bear.
The New Oxford Annotated Bible (NRSV, 2010)
The Global Bible Commentary, Daniel Patte, 2004
First Isaiah: The Hermeneia Commentary, J. J. M. Roberts, 2015