Was Noah’s flood caused by the sudden emptying of a huge glacial lake in Canada, which led to a catastrophic rise in sea level? This was suggested in a 2007 press release from the University of Exeter here in England, quoting one of the university’s professors, with the title ‘Noah’s flood’ kick-started European farming. The same material was also published by ScienceDaily, but with a question mark added to the title.

This press release is about a proper scientific paper published in a respected journal. It must be rare for such papers to mention biblical stories. No creationist pseudo-science is in sight.

I came across this paper while researching for a discussion on Facebook about my recent post Instone-Brewer: Did Noah’s Ark actually happen? One of my friends in that discussion suggested that a flood caused by rivers would not last as long as the biblical flood is said to have lasted. In response I looked into the possibility that the flood could have been caused by a sudden rise in sea level – and found that the Exeter scientists had got there before me.

The culprit, apparently, was Lake Agassiz, a huge prehistoric body of fresh water which covered a large part of what is now Canada and a smaller part of the northern USA, centred in what is now Manitoba. This lake, according to Wikipedia, “held more water than contained by all lakes in the world today”. Its waters were dammed up by the Arctic ice sheet.

As that ice sheet gradually melted at the end of the last major ice age, on at least two occasions the water from Lake Agassiz escaped rather suddenly into the oceans. The first event, around 11,000 BC, is thought to have triggered off a thousand year mini-ice age called the Younger Dryas. Presumably this freeze caused the lake to form again. But renewed warming caused the water from Lake Agassiz and from the linked Lake Ojibway to the east to escape again around 6,400 BC. Again this led to a cold period, but not as long or severe as the Younger Dryas. Since then, it seems, the large glacial lakes have never formed again, although some remnants remain as modern lakes.

The important point concerning Noah’s flood is the rather obvious one that the release of all that water into the oceans caused a significant rise in sea levels worldwide – and one which has never been reversed. Estimates of what Wikipedia calls a “near-instantaneous rise” range up to 4 metres, although the Exeter paper gives a more conservative figure of 1.4 metres.

This rise in sea level would not of course have covered “all the high mountains under the entire heavens”, as recorded in Genesis 7:19 taken literally. But it may have caused especially catastrophic flooding in the Black Sea region. The Exeter paper links this with Noah’s flood. But I would look elsewhere, as David Instone-Brewer does, to low-lying Mesopotamia. What would the effect of the sea level rise have been there?

Now “near-instantaneous rise” should not be taken as implying something like a tsunami. Probably the sea did not spill on to the land in the way seen in recent videos from Japan. But once Lake Agassiz started to break through the ice it could quickly have carved out a very wide channel, and so need not have taken many years to drain. Scientific papers mentioning a period of 200 years are probably only giving a maximum time. There is no reason to doubt the biblical account that the waters rose for forty days (Genesis 7:17), although this is probably to be understood as a round number rather than a precise figure.

The account in Genesis also mentions both that “all the springs of the great deep burst forth” (7:11), a good poetic fit for the bursting of a glacial lake, and that there were forty days of rain (7:12), perhaps caused by the initial disturbance of weather patterns by the rush of fresh water into the oceans – although the following cold spell was generally also dry.

Thus floodwaters flowing down the rivers into Mesopotamia would have met sea water flowing up them. No doubt channels would have become blocked with sand and silt, and a huge low-lying area would have been flooded with nowhere for the water to drain away. The recent Mississippi floods give an idea of how this event might have looked, but there would have been no artificial levees to contain the flooding and no floodways to channel it into the sea. Indeed probably quite a lot of land was permanently lost to the Persian Gulf. But further upstream the floods eventually retreated, but only after 150 days (7:24).

So, I would continue to argue as I did in my previous post, the biblical account if understood as intended, and not as a detailed record of events, tells a realistic story of a huge regional flood which could have happened, which indeed scientists also tell us actually did happen. There is no scientific record of the actual ark, but then one would not expect that. But science agrees with the Bible story in saying that a flood did happen – and adds some interesting details such as that it had its origin in Canada.

As part of a series “Embarrassing Bible Texts?” in Christianity magazine, David Instone-Brewer, of Tyndale House, Cambridge, asks, Did Noah’s Ark actually happen? Were six million land species really rescued in one boat? He concludes that there was a real flood, and a real ark in which “the precious animal stock – specially bred by generations of farmers” was rescued, but that this flood was not worldwide. Neither is he is quite saying that it was a local flood. Rather he links this with a flood attested by proper scientific observation:

Archaeologists in the 1930s found evidence of an amazingly widespread flood (or floods) which covered the whole plain of the Tigris and Euphrates rivers – an area of 140,000 square miles – before 3000 BC. This wasn’t just a shallow flood; even the silt they found deposited by this water was eight feet deep! The whole country is flat, with just a few small hills, so this flood would have been utterly devastating; there is simply no high ground to run to for hundreds of miles. The area was the homeland of the ancient Middle Eastern world and the whole population living there must have been wiped out by this flood. It was a disaster on a scale never seen anywhere in the modern world.

So how can we reconcile this with the Bible passages which appear to teach a worldwide flood:

The waters rose and increased greatly on the earth, and the ark floated on the surface of the water. ¹⁹ They rose greatly on the earth, and all the high mountains under the entire heavens were covered. ²⁰ The waters rose and covered the mountains to a depth of more than fifteen cubits.

Genesis 7:18-20 (NIV 2011)

Instone-Brewer is certainly correct to point out that the Hebrew word eretz, here translated “earth”, can also mean “land”, as in eretz Yisrael which is the normal Hebrew for “the land of Israel”.

More problematic is the phrase “all the high mountains under the entire heavens”. Yes, the Hebrew for “mountain”, har, can also refer to quite a small hill, as in 1 Samuel 26:13. And perhaps “under heaven” can mean within the visible horizon, as Instone-Brewer suggests from Deuteronomy 2:25. But it seems unlikely that “all the high mountains” and “the entire heavens” can be understood in this way.

So how should we understand passages like this? Instone-Brewer seems to treat the Genesis story as a literal account of historical events, and then tries to argue that those historical events did not happen as commonly understood. I don’t think that quite works. It seems to me that if the account is literal, it is about a worldwide flood – one which scientists tell us could never have happened.

However, we need to consider what the authors’ intentions were in writing the accounts in the early part of Genesis, about the creation and the fall as well as the flood. They were not writing scientific papers but stories. And these stories are intended not so much to tell the past as to teach God’s ways – in the case of the flood story, as Instone-Brewer writes,

the message that God hates evil and is willing to take drastic steps to deal with it.

Didactic stories the world over use figures of speech such as hyperbole for dramatic effect. So it would hardly be surprising to find hyperbole in an account like that of the flood. A clear candidate for this kind of hyperbole is Genesis 7:19 quoted above, which turns a flood covering small hills in a local area into a worldwide one reaching above Himalayan peaks.

One might ask, how can one tell which statements in the Bible are hyperbolic, and so can be ignored as unhistorical? But that is the wrong question. If the story is not intended to teach history, one cannot expect to get any reliable historical information from it. That may be frustrating for modern scholars, but it is true. If one wants to know what happened in the past, didactic stories from the Bible or elsewhere may give useful indications, but they can never give the kind of reliable details one might obtain from inscriptions or archives intended as records of events.

In my recent post Harold Camping: once Reformed, now a heretic I suggested that that infamous preacher of the Rapture might have been led astray by his engineering background into

taking Bible verses out of context and reading into them a meaning that their authors and God never intended.

I also suggested that this approach might be typical of creationists. This is seen also in the reading of the Noah’s Ark story as an engineer’s literal report of the height of the water. I suggested in a Facebook comment on the Camping post that

engineers, and physical scientists like myself, tend to be rather literal minded and so to prefer a more fundamentalist approach to the Bible, whereas those trained in the humanities tend to be more liberal theologically.

Well, in this case “those trained in the humanities” (and I am also that) are likely to be better qualified than engineers to understand the implications of the literary genre of the text. If their conclusions seem liberal rather fundamentalist, that doesn’t make them less valid.