Why is Israel using so many dumb bombs in Gaza?

Smart bombs are more precise but less plentiful. More civilians in Gaza may be dying as a result

Dec 16th 2023

On December 12th Joe Biden, America’s president, publicly rebuked Israel for its air war in Gaza. “They’re starting to lose [global] support by indiscriminate bombing that takes place,” he said, in a reflection of his growing impatience. America’s intelligence agencies judge that 40-45% of Israel’s air strikes since October 7th have used unguided or “dumb” bombs, as opposed to precision-guided munitions (PGMs) or “smart” bombs, according to reports first published by CNN. What does that figure reveal?

Laser-guided smart bombs first appeared in the Vietnam war and matured in the 1990s when America invented the joint direct attack munition (JDAM), a GPS-guidance kit that could be attached to ordinary dumb bombs. In the first Gulf war against Iraq in 1991, just 6% of American bombs were PGMs (see chart). When it bombed Serbia in 1999 the rate had risen to 29%. By the Afghan war in 2001 it was 57%—around the same as Israel’s rate today—and 68% by the second Iraq war in 2003.

That Israel is using so many dumb bombs is surprising. Russia still uses a lot: about 95% of those it dropped on northern Syria in 2015 were thought to be unguided. But America and its allies rarely use unguided munitions now. Almost all the bombs dropped by NATO on Libya in 2011 were PGMs. So were around 90% of those that Israel used in the first two weeks of the war.

Marc Garlasco, a former Pentagon weapons expert now at PAX, a Dutch NGO which focuses on civilian protection, says the Israeli figure is “shocking”. The last time America dropped unguided weapons in populated areas was probably its use of cluster bombs on the outskirts of Baghdad more than 20 years ago. Mr Garlasco argues that the lower accuracy of unguided bombs and their wide-area effect might explain why the death toll in Gaza is so high.

In general, PGMs are more accurate and thus more efficient. Studies from the first Gulf war showed that, for many targets, one tonne of PGMs replaced 12 to 20 tonnes of unguided munitions. In Vietnam it took around 30 sorties to destroy one target. In Iraq in 2003 a single sortie could hit up to 16 different targets.

There are probably two reasons Israel is using dumb bombs nonetheless. First, the fighting conditions in Gaza mean that it might be able to strike certain targets using unguided munitions reasonably effectively. An American official told CNN that Israel’s air force was employing dive-bombing—releasing after a steep dive—making its attacks more accurate. Edward Stringer, a retired air marshal in the Royal Air Force, says that this was once a routine tactic, used by British Jaguar ground-attack jets in the first Gulf war. “If you have a small area target, this is as valid an attack as dropping a laser-guided bomb,” he says. “You will achieve accuracy within 20 to 30 feet.” The majority of Israel’s unguided bombs are being dropped on Hamas tunnel entrances in northern Gaza, according to people familiar with the targeting.

A report published last year by Operation Inherent Resolve, the American-led coalition against Islamic State (IS), which has been bombing Iraq and Syria for almost a decade, made the same argument in explaining why Iraq’s air force was using dumb bombs: “properly employing unguided bombs is cheaper than using bombs with costly guidance kits, and can achieve the same effect.” In that campaign, America occasionally dropped unguided bombs ostensibly to crater roads, to constrain the jihadists’ movements, but in practice to raise the morale of Iraqi soldiers who were cheered by evidence of air support, says Stacie Pettyjohn of the CNAS think-tank in Washington.

Each type of munition is delivered in a different way, though. Smart bombs are most accurate when dropped at 15,000 to 23,000 feet, which gives their steering fins ample time to correct their aim, notes Phillip Meilinger, the former dean of the School of Advanced Airpower Studies at the US Air Force’s Air University in Alabama. Dumb bombs need to be dropped from much lower, around 5,000 feet.

That would normally put planes within range of surface-to-air missiles, but Hamas does not have significant air-defence capability. The group has previously used 1970s-vintage Soviet-made Strela-2 or SA-7 shoulder-fired missiles, but these have a relatively low ceiling. Moreover, since the Gaza Strip is barely a few miles wide, Israeli jets are exposed only for a few seconds, not enough time for defenders to acquire a target and launch; Israeli pilots therefore feel safe to dive-bomb.

Detected structural damage, Oct 7th – Dec 12th 2023

Before the ceasefire, Nov 29th

After the ceasefire

Israel’s use of unguided weapons is probably not the main cause of high casualties. More likely, Israel is mostly hitting the targets it wants to hit, including with precision bombs, but is tolerating a high level of civilian harm in the process. The use of unguided bombs may be a contributing factor, however. The PGM is more likely to land squarely in the middle of the targeted area, acknowledges Mr Stringer; the dive-delivered dumb bomb will end up somewhere within it. “The difference between 20 and 30 feet is huge when it comes to the civilians who are living in this environment,” argues Emily Tripp, the director of Airwars, which tracks civilian harm in war.

The Economist’s latest satellite analysis finds that almost 43,000 buildings in Gaza (16% of the total) have been damaged and that at least 450,000 people (20% of the population) are now homeless. “While I’m sure some have been dropped with such pinpoint accuracy,” says Mr Garlasco, “I have grave reservations about such widespread use of this tactic…Though the US and Western militaries train to this standard there’s a reason we use PGMs.”

PGMs, however, are in short supply. That gets to a second possible reason for Israel’s weaponry choices. In the Libyan war many NATO countries quickly exhausted their small stockpiles and had to turn to America. In 2015, 15 months and 20,000 bombs into the campaign against IS, America’s air-force chief acknowledged his service was “expending munitions faster than we can replenish them”. A year after that JDAM kits were being dropped within 48 hours of coming off the production line in Missouri.

In theory, Israel should have plenty in reserve. It has bought around $1.9bn-worth of PGMs from American companies since 2015, including 14,500 JDAM kits and thousands of laser-guided missiles. Since October 7th America has sent at least 15,000 bombs to Israel, including an estimated 3,000 JDAMs. In November Mr Biden told Congress he planned to send $320m-worth of SPICE munitions, which are like JDAM kits.

But Israel’s air campaign has been unusually fierce. It is reported to have dropped 29,000 munitions in total. That is almost exactly as many as America and Britain dropped on the entirety of Iraq in the first month of the war in 2003 and equivalent to just under 500 bombs per day. “This is still significantly higher than what we've seen in any other conflict, at least in the last 20 years,” says Ms Tripp, adding that this includes Russia’s air war in northern Syria since 2015. If American intelligence is correct, Israel will have consumed roughly 16,000 to 17,000 PGMs. Israel is not necessarily running out. Many Israeli officials worry that a bigger war is looming with Hizbullah, a Lebanese militant group. Israel has also threatened to strike the Houthis in Yemen, another Iran-allied militant group that has been firing ballistic missiles towards Israel. These groups, along with Iran, have access to more sophisticated air-defence systems than those of Hamas, capable of striking targets farther away and higher up. Israel’s air force probably wants to preserve its stockpile of smart bombs for these better-defended enemies. ■