DOZENS of previously unknown Michael Jackson songs, including a warning about climate change which he was composing two days before he died, are expected to restore his children’s fortunes in the months and years ahead.

Experts say his music could generate more money during the next 12 months than in the past decade.

The pop icon’s family will release a series of posthumous albums, starting this Christmas, which could not only wipe out debts estimated at $500m (£300m) but also ensure that Michael Jr, 12, Paris, 11, and Prince Michael II, 7, are financially secure for the rest of their lives.

Jackson’s friend Deepak Chopra, the Indian-American New Age guru, revealed that the singer had telephoned him excitedly last week, claiming that he was writing some of his best songs since Billie Jean.

He wanted Chopra, who produced his own poetry album with Madonna and served on the board of Jackson’s Heal the World Foundation, to write the words to a “green hymn”.

Chopra played a fragment of the melody yesterday on ABC’s Good Morning America, revealing a slow brooding organ sound. The message lyrics included the words “trees are our lungs, the air is our breath, the river our circulation”.

Jackson also left songs that remained unfinished during work on his last album, Invincible, released in 2001, which could be completed by other artists. The estates of Tupac Shakur, the rapper murdered in 1996, and Frank Sinatra, who died in 1998, have benefited enormously from posthumous remixes.

Proving the adage that death is the ultimate career enhancer, Jackson songs topped internet download charts in 13 countries this weekend. In America he set a record by taking up 16 of the top 20 places on the iTunes charts. At No 1 was Thriller, adding to its tally as the biggest-selling record.

In Britain his sales have increased by 8,000% since Thursday, with Man in the Mirror expected to top today’s download chart, closely followed by Billie Jean and Thriller, which was written by Rod Temperton, the Clee-thorpes-born musician. HMV, the record chain, said it expected the surge to continue for months.

Jackson sold 750m albums before his death and analysts said yesterday that another 50m could follow by the end of the year.

Business associates confirmed that at the time of his death the Jacksons had already been talking to CKX, a company that has helped to transform Elvis Presley’s Memphis home, Graceland, into the second most visited residence in the United States.

The company’s ideas include a travelling exhibition of Jackson memorabilia, the licensing of theme park rides and an updated version of the musical Thriller Live, first staged in London in 2006.

The estate may even benefit from improvements at Neverland, the former cattle ranch north of Los Angeles which Jackson transformed into a children’s playground. Having spent nearly $100m there, Jackson abandoned the property after his acquittal of child molestation in 2005 and it fell into disrepair.

Last year, days before debt collectors seeking $24m in overdue mortgage payments were due to auction it off, Jackson signed a rescue deal with Colony, a Los Angeles property developer. Colony hopes to put the restored property on the market for up to $90m by the end of the year, with a share of profits destined for Jackson’s children’s trusts.

Colony also cleared out 2,000 mementos, stage costumes and geegaws from the ranch, which Jackson asked a Los Angeles auctioneer to sell off for about $10m. Days later the star grew sentimental, especially about 100 life-sized statues of himself, and stopped the sale.

The auctioneers’ five-volume sale catalogue, originally priced at $200, was being sold on eBay this weekend for $2,000. It was reported yesterday that a signed album by the Jackson 5 which had been expected to fetch $500 in Las Vegas was sold for $27,000.

Although some of Jackson’s personal debts perished with him, trickier claims may be pursued against his estate. He was being sued for $7m said to be owed to Sheikh Abdullah bin Hamad Al Khalifa of Bahrain, who said that he showered Jackson with money after the singer fled at the end of his trial.

Jackson’s smartest business decision - apart from negotiating an unprecedented $2 per record royalty rate in the 1980s – was his $47.5m purchase of ATV, which controlled rights to the Beatles back catalogue.

It earned him $200m before he mortgaged his share down to 5%. The holding is at the core of a protected trust fund which could be worth $1 billion.

Jackson’s children, who were named as primary beneficiaries in a 2002 will, are expected to receive a share of the profits from the first Beatles video game, Rock Band, which could sell more than 1m copies when it is released in September.

“It was sentiment, not business,” a manager said later. “He liked the songs but also wanted to beat his old friend Paul McCartney to the punch.” Most of the 750,000 fans with tickets for Jackson’s 50 planned concerts in London are expected to receive a refund.

Last, private performance

MICHAEL JACKSON summoned up one last great singing and dancing performance the night before he died.

Despite not having given a stage show for 12 years, he engaged in energetic routines while rehearsing for his O2 Arena comeback concerts in London. Some 50 technicians, businessmen and performers watched him behind closed doors at the 20,000-seat Staples Centre arena, Los Angeles - normally the home of the LA Lakers basketball team.

“He didn’t grab water or take a rest, but went from one number to the other,” said Ed Alonzo, a comedian and magician rehearsing alongside Jackson.

It was the second of two rehearsals last week. On Tuesday the production team had been a bit wary as he first stepped on the Staples Centre stage.

“Before last weekend, Michael seemed a bit frail,” said one of the production team. “But as soon as he hit the stage with his dancers on Tuesday, something about him said he really had it - he was electric.”

The set list included Bad, Beat It, Billy Jean, Black or White, Don’t Stop ‘Til You Get Enough, Man In The Mirror, Thriller, Wanna Be Starting Something, and We Are The World.

On both nights, Jackson disregarded “marking” - the rehearsal protocol which states that performers must just go through the motions, so saving themselves for the big night. Instead, he let rip, as if “he had been trying to hold back, but now couldn’t stop himself”, said a member of the production team.

Between numbers, Kenny Ortega, the long-serving director, urged him to take it easy, to save his voice, but Jackson ignored the advice. “He was well rehearsed and seemed to be enjoying pushing himself,” said the source.

Ortega added: “He was happy - we all shared that. We were four or five days from finishing in LA and heading to London, and feeling in really good shape.”

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