As this piece is written, act one of the Gulf of Mexico tragedy continues, agonisingly, to unfold. We, the people of the region, keep hoping to leave behind the terrifying explosions and ghastly loss of human life, the dread invoked by black jets billowing endlessly from below and the floating oil spreading over an ever-growing area.

We want to move on to act two, which will feature many dirty shovels, corpses of birds and people crying over the loss of a landscape they love. Act three has yet to be written; it will employ an enormous cast of lawyers and last for decades, but in that time there will be some healing, we hope. That's what we need to happen as soon as possible, but we can't seem to get the damned thing plugged up.

I am told that Britons like to measure areas by comparison to the size of Wales. The oil spill stretching across the Gulf is now far bigger than Wales; it's about the size of Scotland and growing by more than 1,500 square kilometres (580 square miles) a day. It was my observation, in satellite images of this inexorable spread, that led me to conclude in early May that the rate of release being cited by BP and repeated by our coastguard – 1,000 barrels a day – was preposterous.

After initial pressure, the rate was upped to 5,000 barrels per day – still too low by my estimation by at least a factor of five. BP, however, refused to make any effort to estimate the flow, claiming this could jeopardise its response efforts, which could not possibly be any greater, it avowed.

At this point, three weeks into the calamity, BP had yet to release any video images of the oil gushing from the stricken well. Pressure from journalists eventually pried loose a single, 30-second clip, along with a statement from BP professing surprise that anyone was even interested and the certainty that no one looking at the images could possibly tell what the flow rate was. Not so, it turned out.

Several scientists were able to estimate flow rates at between 40,000 and 100,000 barrels a day. Suddenly a great many people were highly interested in video and other information. Threat of congressional subpoena – a very powerful writ in our system – forced BP to produce more video and eventually the live feed from the bottom we can now see at bp.com. The gusher video went viral.

Now here's the remarkable thing. Through all this, Doug Suttles, head of BP America, appeared day after day on TV insisting that 5,000 barrels a day was the real number. In fact, he said, this number was at the heart of all its engineering calculations for stopping the leak with the dome, the top hat, the top kill, the junk shot and, in last resort, the LMRP cap – whatever that is.

BP, in the words of Suttles, felt deep and sincere concern for the people of Louisiana, and everywhere else where the oil might drift. When a CNN team videoed Louisiana governor Bobby Jindal and other dignitaries afloat in an oil-drenched marsh, Suttles was quickly on the air to profess BP's determination to clean up that "30 acres" of polluted wetland. When several fishermen working on a response team were hospitalised by fumes, he was quick to note the potential danger of "volatile organic compounds" – and just as quick to claim that BP had looked for, but failed to find, any of these nasty VOCs.

My personal experience of the oil spill has been quite different. Last Wednesday my colleagues and I encountered several square kilometres of oil about a centimetre thick; it was 12 miles off the Mississippi delta and more than 50 miles from the leaking well. It comprises several thousand cubic metres poised to come ashore from this patch alone. There are many more like it. Working to sample it – without a skimmer in sight by the way – we would have been overcome by fumes had we not donned respirators. Next day, on boats and planes, we easily documented not 30 acres of oiled marshland, but more than 1,000 in only a portion of the vast, vulnerable delta.

What baffles me is not that BP should seek to minimise the magnitude of the spill. After all, some of our laws would make it liable to penalties of $1,000 per barrel released. Any company would seek to avoid such exposure. What's puzzling is why the company's spokespeople cleave to statements that are so readily refuted.

Casting BP executives as cardboard cut-out villains does not get us very far though. Whatever the courts may find about BP's culpability the real cause is our demand for oil and our refusal to pay its true price. Right now, everyone in America wants to do something to fight the spill. However, if you suggest that perhaps we should double the price of fuel and use the revenue to rebuild our transportation network, the general response is suspicious silence.

Facile comparisons do not do justice to this still unfolding drama. If the climate scientists are even partly right, this could be a dress rehearsal for greater crises: humans instigating vast change we then struggle to control.

Amid such struggles, minimising the spill rate for PR purposes does not stop the leak; engineering stops the leak. Expunging oil from your publicity photos does not clean the beach or tell you how badly damaged was the ecosystem; science does that. In the struggle between spin and science, we must demand that science wins.

• Ian R MacDonald is Professor of Oceanography, Florida State University