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1. A method for producing a formed building material comprising:

a) contacting a gaseous waste stream comprising a CO 2 with water comprising proton removing agent to form a CO 2 charged water;

b) producing a CO 2 -sequestering component from a saltwater solution of divalent cations and the CO 2 charged water under one or more of precipitation conditions favoring precipitation of the CO 2 -sequestering component comprising a metastable carbonate comprising amorphous calcium carbonate, vaterite, aragonite, or combinations thereof; and

c) forming the formed building material from the CO 2 -sequestering component in a process comprising contacting the CO 2 -sequestering component with water, wherein the formed building material is selected from the group consisting of

a) a brick having a compressive strength ranging from 5 to 100 MPa;

b) a block having a compressive strength ranging from 5 to 100 MPa;

c) a tile having a compressive strength ranging from 5 to 75 MPa;

d) a cement board having a compressive strength ranging from 5 to 50 MPa;

e) a drywall having a compressive strength ranging from 1 to 20 MPa;

f) a conduit having a compressive strength ranging from 5 to 75 MPa;

g) a beams having a compressive strength ranging from 35 to 150 MPa;

h) a basin having a compressive strength ranging from 5 to 60 MPa;

i) a column having a compressive strength ranging from 25 to 200 MPa;

j) a fiber-cement siding having a compressive strength ranging from 2 to 25 MPa;

k) a slab having a compressive strength ranging from 10 to 100 MPa;

l) acoustic barrier of at least 0.5 m in length; and

m) insulation material.

2. The method of claim 1 , wherein the gaseous waste stream further comprises NOx, SOx, VOCs, particulates, mercury, or a combination thereof.

3. The method of claim 1 , wherein the formed building material comprises 50% (w/w) CO 2 -sequestering component or more.

4. The method of claim 1 , wherein the CO 2 -sequestering component further comprises bicarbonates.

5. The method of claim 1 , wherein the carbonates has a δ 13 C less than −5‰.

6. The method of claim 1 , wherein the CO 2 -sequestering component further comprises calcite, ikaite, magnesite, barringtonite, nesquehonite, landfordite, amorphous magnesium carbonate, or a combination thereof.

7. The method of claim 1 , wherein the carbonates are metastable such that upon contact with freshwater, the carbonates reprecipiate into freshwater stable compounds.

8. The method of claim 1 , wherein the CO 2 -sequestering component further comprises calcium, magnesium, or a combination thereof.

9. The method of claim 1 , further comprising contacting the CO 2 -sequestering component with an additional component selected from the group consisting of clay, shale, soft slate, calcium silicate, quarried stone, Portland cement, fly ash, slag, aggregate, silica fume, pozzolans, and combination thereof.

10. The method of claim 1 , wherein the CO 2 -sequestering component further comprises co-products of NOx, SOx, VOCs, particulates, mercury, or a combination thereof resulting from conditions used to convert carbon dioxide to carbonates.

11. The method of claim 10 , wherein the CO 2 -sequestering component further comprises sulfates.

12. The method of claim 1 , wherein producing the CO 2 -sequestering component comprises precipitating the CO 2 -sequestering component.

13. The method of claim 1 , wherein precipitating the CO 2 -sequestering component comprises utilizing a low-voltage electrochemical method for removing protons from the solution of divalent cations and the gaseous waste stream comprising CO 2 .

14. The method of claim 1 , wherein producing the CO 2 -sequestering component further comprises dewatering the CO 2 -sequestering component after precipitating the CO 2 -sequestering component, and wherein dewatering the CO 2 -sequestering component produces a dewatered CO 2 -sequestering component.

15. The method of claim 14 , wherein the dewatered CO 2 -sequestering component is directly used in forming the formed building material.

16. The method of claim 15 , wherein at least some water for forming the formed building material is provided by the CO 2 -sequestering component.

17. The method of claim 1 , wherein forming the building material comprises molding, casting, cutting, extruding, sculpting, rolling, compacting, or some combination thereof, the CO 2 -sequestering component.

18. The method of claim 1 , wherein the formed building material has a carbon footprint that is neutral.

19. The method of claim 1 , wherein the formed building material has a carbon footprint that is negative.

20. The method of claim 1 , wherein the formed building material is the drywall.