No, the IPC has not yet declared famine (IPC Phase 5) in [northern] Gaza as a whole. That was merely their projection/forecast for the immediate future, based on their information at the time (about a month ago). The "current status" in their March update was merely phase 4 "Emergency" for all of Gaza
However, their breakdown was that 55% of the population of northern Gaza was in Phase 5 (and anticipated to rise to 70%), while in Rafah only 25% were in Phase 5.
IPC Phase 4 (Emergency) : Households either have large food consumption gaps that are reflected
in very high acute malnutrition and excess mortality; or are able to mitigate large food consumption
gaps but only by employing emergency livelihood strategies and asset liquidation.
IPC Phase 5 (Catastrophe/ Famine) : Households have an extreme lack of food and/or cannot
meet other basic needs even after full employment of coping strategies. Starvation, death,
destitution and extremely critical acute malnutrition levels are evident. For famine classification, area
needs to have extremely critical levels of acute malnutrition and mortality.
Given that more aid has apparently reached the region since then (by Israeli/COGAT reports -- OCHA's are still not updated for March in their all-in-one database for easy comparison) I suspect that the IPC projected worsening has been averted, but time will tell.
If you care what the US said about this (alas only anonymously):
Famine is quite possibly present in parts of the northern Gaza Strip, a senior U.S. State Department official said on Friday, adding that a scarcity of food convoys was an obstacle to getting more aid into the Palestinian enclave under Israeli siege.
"While we can say with confidence that famine is a significant risk in the south and center but not present, in the north, it is both a risk and quite possibly is present in at least some areas," the official told Reuters on the condition of anonymity.
Statement apparently made on March 29 or thereabout.
Yesterday though (April 9), at least the head of USAID acknowledged that the change in the amount of aid was noticeable:
U.S. Agency for International Development Administrator Samantha Power acknowledged on Tuesday that humanitarian aid into Gaza had risen sharply in the past few days, and said the higher level of aid should be sustained and increased further.
"We are seeing a sea change, which we hope is sustained and expanded upon," Power said at hearing of the U.S. Senate Appropriations subcommittee that oversees U.S. diplomatic and foreign assistance spending.
Nonetheless, she added that:
"We have famine-like conditions in Gaza and supermarkets filled with food within a couple of kilometers away," she said at the hearing, which focused on the agency's fiscal 2025 budget request.
This is a bit more technical, but perhaps worth delving into here. For famine to be declared, according to the IPC, it's not enough to have even 100% of the households in "IPC Phase 5 (catastrophe)". But you additionally need specific crude mortality figures:
IPC Phase 5 is referred to as “Catastrophe” when classifying a household and “Famine” when classifying an area. [...]
Catastrophe (IPC Phase 5) -- Occurs when a household has an extreme lack of food and/or other basic needs even after full employment of coping strategies.
Famine (IPC Phase 5) -- Occurs when at least 20 percent of the population in a given area have an extreme lack of food; the Global Acute Malnutrition prevalence (measured by weight-for-height z-score) exceeds 30 percent; and mortality (measured by the Crude Death Rate) exceeds 2 people per 10,000 per day.
(Some other agencies like MSF have called the latter bit [of any] standard i.e. a fixed mortality threshold questionable, but it is what it is.)
It looks like the last time the IPC declared a famine was in Somalia in 2011 (more specifically, just in two regions in the south of the country. Affected population according to the IPC brochure: about half a million. This is actually a lot less than what Wikipedia indicates, based on the initial IPC projection for that.) Actually, there was a more recent one: South Sudan in 2017, in a small central region (Leer and Mayendit counties--population affected 80,000 according to the IPC brochure).
