SUMMARY: Naked-eye moonsighting gives the 1st day of Ramadan 1443 as Sunday 3 April 2022 for the whole world except for North America where Saturday 2 April 2022 is a possibility. Moonsighting with a telescope gives the 1st day of Ramadan 1443 as Saturday 2 April 2022: some authorities and countries have already announced Ramadan for then. (Naked-eye moonsighting in Antarctica & New Zealand might give the 1st day as Monday 4 April 2022!)
Astronomical new moon occurred at 06:24 UT (GMT) today, on Friday 1 April 2022 (29 Sha’ban 1443).
Crescent (lunar) visibility diagrams, courtesy of the UK HMNAO/IOP Moonwatch project, now hosted by UKHO:
Friday 1 April 2022 / 29 Sha’ban 1443, evening
(around the optimal time for moonsighting, about 20 minutes after sunset):

Global new (crescent) moon visibility for the evening of Friday 1 April, 2022 (29th Sha’ban 1443):
Not visible anywhere in the world, with the exception of the Americas.
The new crescent moon will be visible by naked eye in California, Mexico & parts of Central America, and by telescope in parts of South America. Given the ISNA Fiqh Council’s very reasonable judgment since the 1990s that North America is to be regarded as one horizon (matla’), this would lead to the 1st day of Ramadan 1443 being Saturday 2 April 2022 throughout North & Central America. If sighting by telescope is deemed acceptable, the same start date would apply to South America. However, I defer to the judgments of the relevant authorities in the Americas.
Saturday 2 April 2022 / 30 Sha’ban 1443, evening
(around the optimal time for moonsighting, about 20 minutes after sunset):
Global new (crescent) moon visibility for the evening of Saturday 2 April, 2022 (30th Sha’ban 1443):
Visible throughout the whole populated world, with the exception of Antarctica & most of New Zealand, where it will be visible the following evening.
Thus, for Oceania (with the possible exception of New Zealand), Asia, Africa & Europe,
the 1st day of Ramadan 1443, based on local moonsighting, is Sunday 3rd April 2022.
Have a blessed & peaceful Ramadan: let us pray for, and serve, our brothers and sisters in humanity!
(Imam Dr) Usama Hasan,
Fellow of the Royal Astronomical Society, London, UK
29th Sha’ban 1443 / 1st April 2022
Postscript: The European Council for Fatwa & Research announced on 16/02/2022 that the 1st day of Ramadan for the whole world would be on Saturday 2nd April 2022, based on “detailed astronomical calculations.” They claim that these showed that the new crescent moon (hilal) would be visible “by telescope in West Africa and the Americas” after sunset on Friday 1st April 2022. This seems to be based on the Odeh model. I agree with their approach of determining Islamic lunar dates via astronomical calculations, but we need to agree which ones we are using. ECFR are accepting telescope observations, whereas many of us prefer naked-eye sighting. NB: the Odeh model predicts a narrower range of territory for naked-eye sighting, as is clear from the following visibility maps: