chuong 7- cac van de nen tang ve mt.ppt

CHNG 7

CC VN NN TNG V MI TRNG

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7.1. VN DN S

Dn s
Dn s (population) l i lng tuyt i con ngi trong mt n v hnh chnh hay mt quc gia, mt chu lc hoc c hnh tinh chng ta ti mt thi im nht nh. Dn s ca mt cng ng, mt quc gia ph thuc vo qu trnh sinh t. Ngoi ra cn ph thuc vo mt s yu t khc nh kt hn, ly hn, gin hn v c bit l xut nhp c.

Tng quan lch s
Dn s u cng nguyn c khong 200-300 triu ngiNm 1650 c khong 500 triu ngiNm 1850 tng gp i l 1 tNm 1930 tng gp i l 2 t

c im ca s pht trin dn s th gii

Giai on s khai.
T tin loi ngi vi triu nm trc y c khong 125.000 ngi tp trung sng Chu Phi. Thi k ny, con ngi sn bt, hi lm, ch bin thc n, quy c x hi... S tin ha ca loi ngi gn lin vi s pht trin ca no b. S tin ha no b din ra cho n khong 200.000 nm trc y khi xut hin cc c th mi khc hn v cht ca cng loi m ta gi l ngi khn ngoan- Homo sapiens.S tin ha v vn ha c mt s tc ng ph ti s gia tng dn s. Dn s thi k ny c t l sinh khong 40%o-50%o

Giai on cch mng nng nghip

Canh tc nng nghip xut hin vo khong 7000 - 5500 B.C vng Trung ng v ngi dn trng nhiu loi cy v chn nui gia sc.C cu t chc x hi mi theo hng phn cng lao ng xut hin. Tui th trung bnh tng hn thi k nguyn thu

Giai on sau Cch mng nng nghip

Sau Cch mng nng nghip, s gia tng dn s khng tip din lin tc, lc tng lc gim, nhng c bn vn l tng.

c im ca s pht trin dn s th gii (tt)

Giai on tin Cch mng cng nghip ( 1650 - 1850)
T gia th k XVII, th gii bc sang mt giai on n nh ho bnh sau ch kinh t phong kin. Cng vi cuc cch mng nng nghip Chu u, cuc cch mng thng mi th gii tr thnh ng lc pht trin kinh t x hi th gii vo th k XVIII.

Giai on cch mng cng nghip ( 1850 - 1930)
n gn cui th k XIX xut hin mt khuynh hng khc ko theo t l sinh gim xung cc nc phng Ty. N nh du mt thi k v dn s m ta gi l s chuyn tip dn s. T l tng bnh qun trong thi gian ny l vo khong 0,8%/ nm. Dn s th gii tng t 1 t ln 2,5 t ngi. Trong qung thi gian ny, dn s Chu tng di 2 ln, Chu u v Chu Phi tng 2 ln, Bc M tng 6 ln v Nam M tng 5 ln.

Giai on hin i ( t 1930 - nay)

Sang th k XX, khuynh hng trn thay i dn. T nhng nm 40, dn s th gii bc vo giai on mi: " giai on bng n dn s"



Theo cc kch bn khc nhau v tc tng trng dn s th gii, dn s ton th gii vo nm 2050 s c cc gi tr :

- Tc tng trung bnh 1,7% dn s th gii 14 t

- Tc tng trung bnh 1,0% dn s th gii 10 t

- Tc tng trung bnh 0,5% dn s th gii 7,7t

S bin i dn s trong cc quc gia

Ph thuc vo
S pht trin ca nn cng nghip Chnh sch pht trin dn s

Quan h gia dn s v MT
Tc ng MT ca s gia tng dn s th gii c th m t bng cng thc tng qut:
I = C.P.E

trong :
C - s gia tng tiu th ti nguyn trn n v u ngiP - s gia tng tuyt i dn s th giiE - s gia tng tc ng n MT ca mt n v ti nguyn c loi ngi khai thc I - tc ng MT ca s gia tng dn s v cc yu t lin quan n dn s

Cc tc ng tiu cc ca tnh trng gia tng dn s hin nay trn th gii
Sc p ln ti TNTNv MT Tri t do khai thc qu mc cc ngun ti nguyn phc v cho cc nhu cu nh , sn xut lng thc, thc phm, sn xut cng nghip,...To ra cc ngun thi tp trung vt qu kh nng t phn hu ca MT t nhinS chnh lch v tc pht trin dn s gia cc nc cng nghip ho v cc nc ang pht trin gia tng, dn n s ngho i cc nc ang pht trin v s tiu ph d tha cc nc cng nghip ho S gia tng dn s th v s hnh thnh cc thnh ph ln- siu th lm cho MT khu vc th c nguy c b suy thoi nghim trng

Mi quan h gia dn s v pht trin bn vng
Mc tiu t ra i vi quc gia, lnh th l m bo dn s n nh, pht trin kinh t x hi bn vng m bo cht lng cuc sng tt cho cng ng. Dn s v pht trin tc ng qua li cht ch vi nhau.Bc tin ca lnh vc ny thc y, to thun li cho lnh vc kia. Gii quyt tt dn s nhng kinh t x hi khng pht trin th cht lng cuc sng cng khng c m bo. Ngc li kinh t x hi pht trin nhng dn s tng qu cao th tng sn phm quc ni theo u ngi (GDP) s st gim v cui cng cht lng cuc sng vn c thp.
Vn t ra cho ton th gii l vic lng ghp vn dn s vi pht trin m bo s hi ha.

6 vn quan trng nht cn gii quyt nhm m bo s hi ha gia dn s v PT

1. Thc hin chnh sch k hoch ha gia nh v xy dng quy m gia nh hp l, y mnh dch v k hoch ha gia nh, phng trnh thai, t vn sc khe tnh dc.

2. Dn s gn vi pht trin kinh t bn vng, m bo cng bng x hi.

Cc ni dung chnh nh gii quyt vic lm, gim tht nghip; y mnh chng trnh xa i gim ngho, to vic lm hn l cho tin ca; Chm sc sc khe cng ng; Pht trin gio dc.

3. Chnh sch v chng trnh c th i vi nhng nhm c th nh v thnh nin, ngi gi, ngi tn tt (trong thp nin ti ngi gi s tng 8-25%), ngi dn tc thiu s.

4 .Chnh sch v mi trng s dng hp l ti nguyn mi trng pht trin bn vng.


5. Chnh sch x hi v di c. Thc hin di c c quy hoch, k hoch nm trong phng hng chin lc ti phn b dn c v lao ng gim sc p ni qu ng dn, nhng khng c mang con b ch.

6. Chnh sch v th ha. th ha l xu hng tt yu ca qu trnh pht trin kinh t x hi l xu hng chuyn i t x hi nng thn l ph bin sang x hi th l ph bin ti cc nc pht trin v ang pht trin.


T l gia tng dn s Vit Nam qua cc thi k

5.2. VN LNG THC

THC PHM

Nhng lng thc v thc phm ch yu
Cho n nay, loi ngi thun ha n nay chng 80 loi cy lng thc, thc phm ch yu v trn 20 loi ng vt. V lng thc ch yu c 3 loi: la, la m v ng vi qu na din tch t ai trng trt ca Tri t. Ch ring la v la m cung cp chng 40% nng lng dng thc n cho loi ngi.

C khong 45 hp cht v nguyn t c trong cc loi lng thc v thc phm c coi l cc cht dinh dng quan trng, cn thit cho cuc sng v sc kho ca con ngi. Cc cht dinh dng ny nm trong 5 nhm l glucit, lipid, protein, viatmin v mui khong. Mi cht dinh dng ny c th c tm thy trong cc loi lng thc v thc phm khc nhau, tuy nhin khng c loi thc n no c th cha y cc hp cht cn thit. Mi mt loi thc n c mt chc phn hay cc chc phn khc nhau trong c th, nh cung cp nng lng, xy dng cc m hay duy tr cc qu trnh sinh l c bn ca c th.

Sn xut lng thc v dinh dng th gii

Tim nng lng thc v thc phm ca th gii

Cc thnh tu ca cch mng xanh

- Cch mng xanh c 2 ni dung quan trng h tr v b sung cho nhau l to ra nhng ging mi v nng sut cao ch yu l cy lng thc v s dng t hp cc bin php k thut pht huy kh nng ca cc ging mi

- Cch mng xanh to ra nhng thnh tu ln trong sn xut lng thc ca th gii. Bn cnh cch mng xanh cng to ra nhng hn ch

Tim nng sn xut lng thc v thc phm ca bin

Bin v i dng th gii l kho d tr lng thc v thc phm ca con ngi

Sn lng nh bt hi sn ca th gii n nm 2000 ( triu tn)

(UNEP, 1983)

5.3. VN NNG LNG

Khi nim.

Nng lng l mt dng vt cht, xut pht t hai ngun ch yu l nng lng Mt Tri v nng lng lng t.
Nng lng Mt Tri : Bc x Mt Tri, nng lng sinh hc di dng sinh khi ng thc vt, nng lng chuyn ng ca kh quyn v thu quyn, nng lng ho thch.Nng lng lng t : ngun nc nng, ni la v nng lng phng x ca cc m U,Th, Po

Khi nim.

Nhu cu nng lng ca con ngi gia tng nhanh chng trong qu trnh pht trin:

- 100.000 nm trc cng nguyn : mc tiu th khong 4.000- 5.000 Kcal/ ngi/ nm

- Th k 15 : 26.000 Kcal/ ngi/ nm

- Gia th k 19 : 70.000 Kcal/ ngi/ nm

- Hin nay : 200.000 Kcal/ ngi/ nm

S khc bit v c cu ngun nng lng v i tng s dng nng lng gia hai nhm nc cng nghip pht trin v ang pht trin th gii nm 1987

T l s dng ngun nng lng Th gii cc nc khc nhau

Cc dng nng lng v s bin i.

C th phn loi cc dng nng lng theo cc phng cch nh sau:
Theo kh nng ti to: nng lng ti to v khng ti toTheo kh nng gy nhim: nng lng sch v nng lng gy nhimTheo kh nng trao i v bun bn: nng lng thng mi v phi thng miTheo bn cht nng lng: nng lng BXMT, nng lng ho thch, nng lng thu triu, gi, thu in, phng x, nng lng sinh khi
Tng hp tt c cc tiu ch trn c th phn chia ngun nng lng trn T thnh mt s dng c bn :

-Cc dng ti nguyn nng lng khng ti to v c gii hn

-Cc dng nng lng khng ti to v vnh cu

Cc dng nng lng vnh cu v ti to

Nng lng in

Vn pht trin in nng vit Nam v s pht trin kinh t?

Nguyn nhn?

- Tn tht v lng ph nhiu

- Hiu qu s dng in nng thp

- Ti nguyn, nht l nhin liu ha thch, nhanh chng cn kit

- Mi trng b nhim mc ti hn.

Cc gii php v nng lng ca loi ngi

- Son tho nhng chin lc quc gia v nng lng cho thi gian 30 nm ti.

- Hn ch s dng cc loi nhin liu ha thch, s lng ph trong phn phi nng lng v nhim mi trng trong sn xut nng lng thng mi.

- Pht trin cc ngun nng lng ti to c v nng lng khng ha thch.

- S dng nng lng c hiu qu cao hn na.

Pht ng cc chin dch truyn thng tit kim hn na.

- Gim bt s pht thi kh nh knh ang l vn cn c u tin

Chin lc nng lng Vit Nam

Hin nay, Vit Nam vn cha c mt chin lc v chnh sch nng lng. Tuy nhin, da vo cc vn bn lin quan n bo v mi trng quc gia th c th pht tho mt khung chin lc nng lng Vit Nam, gm cc im sau:

Chin lc v ngun nng lng;

Chin lc tit kim tiu dng nng lng thng mi;

Chin lc u tin pht trin v s dng nng lng sch, nng lng ti to quy m nh.

Sn xut in nng t hi nc trn mt bin
C mt hin tng t nhin thng xuyn xy ra trn bin, l khi cc tia nng mt tri chiu xung nc, lng nc trn b mt s bt u b nng ln v bay hi. Li dng hin tng ny, cc nh khoa hc a ra tng sn xut in nng t hin tng ny. Cng trnh c tn gi OTEC (ocean thermal energy conversion - chuyn i nng lng t hi nc trn i dng).

Theo , ngi ta s tn dng lng nc c mt tri lm nng trn b mt bin lm nng cc kh ammonia v cc cht lng c nhit si thp. Mc ch ca cng vic ny l to ra lung kh gas y cc tua-bin quay nhm sn xut ra in. Lng kh gas sau li c lm lnh bi nc di bin v ti s dng tr li.Qu trnh ny din ra lin tc s lm cho cc tua-bin lin tc hot ng sn xut ra in nng. Theo cc nh khoa hc, y l ngun in nng v cng di do. 1/10 ca 1% lng nng lng mt tri c hp th trn mt i dng, c th gip sn xut ra lng in ln gp 20 ln lng in cn cung cp cho nhu cu ca nc M trong mt ngy. Vn duy nht l chi ph cho vic xy dng nhng cng trnh quy m nh vy trn bin, qu l con s khng nh
Sn xut in nng t hi nc trn mt bin

Nng lng t kh hydro
to ra ngun nng lng ny, ngi ta cn sp xp cc ngn cha hydro dng lng v ng dn cho kh hydro ny phn ng vi kh xy to thnh dng electron lm quay mt in. Ngun nng lng ny ch yu dng vn hnh cc loi xe t thn thin vi mi trng. Cht thi duy nht m cng ngh sn xut nng lng mi ny to ra l nc (kt qu ca s kt hp gia hydro v xy)

To ra nng lng t sng bin
lm c iu ny, cc nh khoa hc s dng ti mt thit b thy ng hc ging nh hnh dng ca chic ci xay gi hot ng trong nc. Khi nc t cc dng sng hoc cc con sng trn bin tc ng vo thit b s lm quay cc tua-bin v lm pht ra dng in. V nguyn l hot ng v to ra in nng ca h thng ging y ht nh nhng chic ci xay gi. Gii khoa hc nh gi y l ngun nng lng v cng di do m nhn loi c th tn dng, ng thi c th gip tri t gim c tc ng ca hiu ng nh knh

Tn dng ngun nhit nng ca tri t
Trn b mt tri t c mt ngun nhit nng khng l m con ngi cha khai thc, tn dng, mt trong s ngun nng lng l sc nng t cc ni la.
Cc nh nghin cu cho rng, con ngi c th s dng ngun nhit nng di do ny to ra in nng cung cp cho cc hot ng nhng ni cng cng, chng hn nh n chiu sng trn cc ng ph.

y l ngun nng lng sch, phong ph v ha hn s c khai thc trong tng lai khng xa.

Nng lng t gi
So vi cc cnh ng "ci xay gi" quy m ln, th h thng sn xut nng lng t gi vi quy m nh c th cung cp lng in dng cho tng gia nh.H thng ci xay gi mini trung bnh c th sn xut c t 1 - 10kw in, cung cp lng in nng thp sng v cc thit b s dng in khc trong mt nginh.

Nng lng mt tri
Th gii hin c hai cch thu nng lng mt tri
- S dng cc h thng gng tp trung nh sng mt tri lm nng nc nhm to ra hi nc y quay cc tua-bin pht in,

-S dng cc tm pin mt tri chuyn ha nhit nng thnh in nng.
C hai phng php ny hin u c p dng v ang mang li hiu qu rt cao.

Nng lng ht nhn
Cc quc gia pht trin trn th gii hin ang s dng ch yu loi nng lng ny v trong tng lai, nng lng ht nhn vn s l u tin s mt i vi nhiu quc gia trn th gii. Ch tnh ring ti M, quc gia ny hin ang ln k hoch xy dng mi thm 100 l phn ng ht nhn nhm cung cp in nng cho 1/5 dn s quc gia.

5.4. VN BIN I KH HU

nh ngha
Bin i kh hu l nhng bin i trong mi trng vt l hoc sinh hc gy ra nhng nh hng c hi ng k n thnh phn, kh nng phc hi hoc sinh sn ca cc h sinh thi t nhin v c qun l ca cc h thng kinh t - x hi hoc n sc khe v phc li ca con ngi.
(Theo cng c chung ca LHQ v bin i kh hu).

Nguyn nhn
Nguyn nhn chnh lm bin i kh hu Tri t l do s gia tng cc hot ng to ra cc cht thi kh nh knh, cc hot ng khai thc qu mc cc b hp th kh nh knh nh sinh khi, rng, cc h sinh thi bin, ven b v t lin khc. Nhm hn ch s bin i kh hu, Ngh nh th Kyoto nhm hn ch v n nh su loi kh nh knh ch yu bao gm: CO2, CH4, N2O, HFCs, PFCs v SF6.

Nguyn nhn (tt)
CO2 pht thi khi t chy nhin liu ha thch (than, du, kh) v l ngun kh nh knh ch yu do con ngi gy ra trong kh quyn. CO2 cng sinh ra t cc hot ng cng nghip nh sn xut xi mng v cn thp. CH4 sinh ra t cc bi rc, ln men thc n trong rut ng vt nhai li, h thng kh, du t nhin v khai thc than. N2O pht thi t phn bn v cc hot ng cng nghip. HFCs c s dng thay cho cc cht ph hy zn (ODS) v HFC-23 l sn phm ph ca qu trnh sn xut HCFC-22. PFCs sinh ra t qu trnh sn xut nhm. SF6 s dng trong vt liu cch in v trong qu trnh sn xut magi.

Cc biu hin ca bin i kh hu
S nng ln ca kh quyn v Tri t ni chung. S thay i thnh phn v cht lng kh quyn c hi cho mi trng sng ca con ngi v cc sinh vt trn Tri t. S dng cao mc nc bin do bng tan, dn ti s ngp ng cc vng t thp, cc o nh trn bin.

Cc biu hin ca bin i kh hu (tt)
S di chuyn ca cc i kh hu tn ti hng nghn nm trn cc vng khc nhau ca Tri t dn ti nguy c e da s sng ca cc loi sinh vt, cc h sinh thi v hot ng ca con ngi. S thay i cng hot ng ca qu trnh hon lu kh quyn, chu trnh tun hon nc trong t nhin v cc chu trnh sinh a ho khc. S thay i nng sut sinh hc ca cc h sinh thi, cht lng v thnh phn ca thu quyn, sinh quyn, cc a quyn.

BIN I KH HU VN
-Vn tri t nng ln, nc bin dng cao v kh hu ang bin i mt cch khc nghit n nay khng cn l chuyn ca th gii, m ang e do trc tip n VN: L lt, hn hn, triu cng ngy cng nng n hn, nh hng trc tip n s an ton ca con ngi v c nn kinh t.

BIN I KH HU
Trong nhng nm gn y, c bit trong ng cnh chnh sch mi trng, bin i kh hu thng cp ti s thay i kh hu hin nay, c gi chung bng hin tng nng ln ton cu.
Nguyn nhn chnh lm bin i kh hu tri t l do s gia tng cc hot ng to ra cc cht thi kh nh knh, cc hot ng khai thc qu mc cc b hp th v b cha kh nh knh nh sinh khi, rng, cc h sinh thi bin, ven b v t lin khc.

BIN I KH HU
Theo nghin cu ca T chc Hp tc v Pht trin kinh t (OECD), TP H Ch Minh nm trong danh sch 10 thnh ph b e do nhiu nht bi bin i kh hu (bao gm Calcutta v Bombay ca n , Dacca ca Bangladesh, Thng Hi, Qung Chu ca Trung Quc, TPHCM ca VN, Bangkok ca Thi Lan v Yangon ca Myanmar).

BIN I KH HU
Theo bn bo co v pht trin con ngi 2007-2008 ca UNDP, nu nhit trn tri t tng thm 2 C, th 22 triu ngi VN s mt nh v 45% din tch t nng nghip vng ng bng sng Cu Long, va la ln nht ca VN s ngp chm trong nc bin.Bin i kh hu c th dn n 5 nguy c ln:
Gim nng sut nng nghip;

gia tng tnh trng thiu nc;

thi tit cc oan gia tng;

cc h sinh thi tan v

bnh tt gia tng.

BIN I KH HU
Vi trn 3.000km b bin, VN c coi l quc gia c mc d b tn thng cao hn trc s bin i kh hu. Cc huyn ven bin tnh Ngh An thi gian gn y ang b nc bin xm ln n mc bo ng. Nhiu x nm cch b bin t 5 n 10km, nhng v ang b nc mn tn cng.

BIN I KH HU
Theo thng tin do Vin Khoa hc Kh tng thu vn v Mi trng (KT-TV&MT) a ra ti hi tho khoa hc thng nin 2007 mi t chc ti TPHCM, BSCL s ngp 1.708km2 t. Theo thng k, BSCL c tng din tch 34.322km2, trong 18.066km2 t thuc cc huyn ven bin. Trong cc thp k gn y, yu t kh tng thu vn ti BSCL tip tc thay i theo chiu hng xu. Cc thin tai nh bo t, lt li, xm nhp mn... xy ra thng xuyn hn v kh d on.

PHNG HNG GII QUYT

Phng hng-Chin lc
Mang tnh ton cu: y l vn chung ca cng ng, khng phi l ring bit ca tng quc gia, khu vc hay chu lc no. c cc quc gia nht tr: ra cc phng hng v phn cng nhim v cng bng hiu qu gia cc quc gia, khu vc hay chu lc.C quy m: ln, rng khp v mi mt v lun da trn nguyn tc thng nht ng b. Thc hin nhanh chng: hnh ng sm t hiu qu cao

PHNG HNG GII QUYT

Bin php
Tng cng tuyn truyn gio dc thc cng ng: theo nguyn tc ton din, tch cc v hiu qu: lng ghp cc thng ip chnh v cc thng tin ph hp lin quan n bin i kh hu vo k hoch bi ging phng nga thm ho dnh cho cp x, ng thi qua gii thiu hu qu ca BKH c tc ng trc tip n ton b hnh tinh ca chng ta.

PHNG HNG GII QUYT

Bin php
Tng cng n lc gim thiu hin tng kh thi gy hiu ng nh knh: bng cch a ra chin lc thit thc gim cacbon. Hp tc quc t.
nh gi cho pht thi cacbon .

Chuyn nhu cu sang cc ngun nng lng cacbon thp.

Bin php

Xy dng cc cng c php l.

Phc hi ca cc h sinh thi:

Trng rng.

Bo tn cc h sinh thi ng thc vt
Hon chnh h thng vn bn php lut. Pht trin kinh t x hi da trn cc nguyn tc bn vng.

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chuong 7- cac van de nen tang ve mt.ppt