At mid-decade, demographic trends in Chicago, as revealed by the 2000 census, have accelerated. By 2010 the city's population will consist of more whites, many more Hispanics, and fewer blacks. Here's why:

First, the city's white population is exploding in the South Loop, Dearborn Park and Chinatown, as well as westward from the University of Illinois-Chicago/medical center complex along the Eisenhower Expressway, all the way Garfield Park, at Pulaski and Madison. Like squeezing a tube of toothpaste, blacks are being pushed out of those areas.

Second, the city's Hispanic population, exploding along the Grand Avenue corridor on the northwest and in the southwest corridor between Ogden and Archer avenues, is pushing blacks out of those areas. New Hispanic-majority wards will surely be created on both the Northwest Side, around Belmont-Central and Cragin, and on the Southwest Side.

Third, the wards around Midway Airport on the Southwest Side controlled by former U.S. representative Bill Lipinski and Illinois House Speaker Mike Madigan, the 23rd and 13th wards, respectively, have growing Hispanic populations. The east end of Madigan's ward, west of Central Park, between 55th and 83rd, is now heavily Hispanic, as is the north part of Lipinski's ward, north of 51st around Laramie. Within a decade, a Hispanic ward will have to be carved out of those two wards, now represented by white aldermen Mike Zalewski (23rd) and Frank Olivo (13th).

And fourth, the gentrification of Rogers Park, replete with upscale condominiums, usually from conversions of apartment buildings, is pushing minorities out of the area north of Devon and east of Damen and into Evanston and Skokie. The black population north of has been almost totally dispersed.

For Chicago's 50 aldermen, that's both bad news and good news. The bad new is that some will be running in demographically changing wards in 2007 and 2011, facing difficult re-election races. The good news is that they'll be running within the same boundaries in both 2007 and 2011, and they won't face the prospect of a reconfigured ward until 2015, because the results of the 2010 census won't be available until mid-2011, the filing deadline for the 2011 city election is December 2010, and the 2011 election will be in February.

At present, the city has 19 black aldermen with 20 black-majority wards, eight Hispanic aldermen with 10 Hispanic-majority wards, and 23 white aldermen with 20 white-majority wards. That will change.

Four black-majority wards are undergoing major demographic upheaval: The Near South Side 2nd Ward and the West Side 24th Ward have growing white populations, and the Far West Side 37th Ward and 29th Ward have growing Hispanic populations. So, too, are some white areas. On the Northwest Side, the wards of white Aldermen Tom Allen (38th), Bill Banks (36th) and Dick Mell (33rd) also have growing Hispanic populations.

When Chicago's wards are redrawn after the 2010 census, the city likely will have two fewer black aldermen, four more Hispanic aldermen and two fewer white aldermen. One possible casualty is Allen, since the east end of his 38th Ward, north of Belmont between Narragansett and Cicero, is increasingly Hispanic, as is the northeast corner of Banks' ward, north of Fullerton and east of Harlem. That area will constitute part of a new Hispanic-majority ward, which will result in the white areas of Banks' and Allen's wards being consolidated into a new white-majority ward. Should that occur, Banks, the City Council Zoning Committee chairman, would be favored to beat Allen.

Also in jeopardy is Alderman Emma Mitts (37th). Her black-majority ward, in east Austin and West Garfield Park, which extends from Central to Pulaski, between Chicago and Fullerton, but south of Grand, has a growing Hispanic population, particularly along the Grand Avenue corridor. In 2003, against four opponents, Mitts won with 73 percent of the vote.

The same trend is occurring in the predominantly black 29th Ward, represented by Alderman Ike Carothers. The ward, in west Austin, extends from Roosevelt to Belmont, between roughly Austin and Laramie, but jogs west to Narragansett north of North Avenue. The north part of the ward, north of Fullerton, is now Hispanic. In 2003, against two foes, one being white, Carothers got 75 percent of the vote.

Territory from the 38th, 36th, 37th and 29th wards will be more than enough to populate a new Hispanic-majority ward. That would mean putting Mitts and Carothers in a new black-majority ward, with Carothers favored to win.

Two black wards that are trending toward a white majority are the 2nd, represented by Alderman Madeline Haithcock, and the 24th, represented by Alderman Mike Chandler, both of whom are black. The 2nd Ward includes the South Loop, encompassing Dearborn Park, Chinatown, Soldier Field and McCormick Place, and extends from Pershing north to Balbo, and hooks west to Sacramento, running along the Eisenhower Expressway.

The 2nd and 24th wards take in the entire Eisenhower Expressway corridor, all the way west from Michigan Avenue to Laramie. That corridor, from the Loop and the UIC/medical center complex westward, stretching as far north as Madison and as far south as Roosevelt, has been gentrified, with minority housing being demolished and replaced. New $400,000-plus homes, usually two-story cinderblock fortresses, have been built, and they are inhabited mainly by whites. From the United Center, at Damen and Madison, to Garfield Park, between Kedzie at Pulaski along Madison, the white population is growing.

The 24th Ward's North Lawndale area, extending from California to the city limits, between Cermak and Jackson, was nearly all black as recently as the early 1990s. Now the white population is growing in the north end and the Hispanic population is growing in the south end, with Hispanics expanding north of Cermak and west from Douglas Park.

The 2nd Ward, taking in the Near South Side and parts of Armour Square and Douglas, is now more than 30 percent white. A decade ago upscale condominiums and townhomes were being built as far south as 11th and State; now they're as far south as 18th Street, and soon they will be encroaching on Bronzeville, at 26th Street. The ward's committeeman since 1984 is U.S. Representative Bobby Rush (D-1), who engineered Haithcock's appointment to succeed him as alderman in 1993. They have since become estranged, and Rush refused to endorse her in both 1999 and 2003. Haithcock won with 64 percent of the vote in 1999, with Rush's sister-in-law getting just 18 percent, and Haithcock got 55 percent of the vote in 2003, with a white candidate getting 20 percent. A black candidate who appeals to white voters could win this seat in 2007.

In the post-2010 remap, the Hispanic majority in the south portion of the 24th Ward will surely be added to the adjacent 22nd Ward (Cermak to Pershing, west of Kedzie), in South Lawndale. Chandler won with just 53 percent of the vote in 2003, way down from his 77 percent in 1999. As in the 2nd Ward, a black candidate who appeals to Hispanic and white voters or a white or Hispanic who appeals to blacks could upset Chandler in 2007.

To keep a black majority in the 24th Ward, it would have to move east to take in some of the west part of the 2nd Ward, which is the area between 16th and Harrison, between Racine and Western. And if that occurs, the 2nd Ward would become even less black. In fact, a white-majority ward could be created from the north part of the 2nd Ward, extending west along the Eisenhower to Garfield Park. That, however, is politically impractical. So what will occur is the creation of two black wards with large white minorities, in which a white candidate could win, if not in 2015, then later.

Alderman Ed Burke's South Side 14th Ward, around Brighton Park, Gage Park and Archer Heights, is already overwhelmingly Hispanic. Burke's political and monetary clout have kept him insulated from a Hispanic challenger, but that may not persist into the next decade. In the Far South Side 10th Ward, encompassing Hegewisch and South Deering, south of 83rd Street and east of the Calumet Expressway, Alderman John Pope also is secure, even though the ward is more than 60 percent Hispanic.

But the same can't be said of the 13th and 23rd wards. In any post-2010 remap, the territory in those two wards would be divided, with one being a Hispanic-majority ward and with Olivo and Zalewski put in the white-majority ward.

The bottom line: The 2000 census put Chicago's population at 2.9 million, breaking down as 42 percent white, 37 percent black and 21 percent Hispanic. Hispanic population growth will lift the city's population to more than 3 million by 2010. Because of central city development, white population will increase slightly, and because of Hispanic expansion into heretofore black areas, the city's black population will decline.