Background
Dams are widely associated with malaria
Dam-malaria impacts do not occur in a vacuum
Climate change may alter dams’ impact on malaria
No study has examined future impacts of dams in light of climate change
Estimating impact
Methods
Study area
Data source
Data on existing African dams
Estimating reservoir perimeters
Malaria data
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stable transmission in areas with annual PfIR greater than 0.1 cases per 1000 population;
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unstable transmission in areas with annual PfIR between 0 and 0.1 cases per 1000 population; and
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no malaria in areas having zero annual PfIR.
Future climate scenarios
Population data
Statistical analysis
Mapping dams and malaria in climate change scenarios
Estimating population at risk around dams
Estimating future malaria incidence around reservoirs
Estimating future malaria cases associated with dams
Identifying the increase in malaria cases attributable only to population increase
Identifying the increase in malaria cases attributable only to climate change
Results
Spatial distribution of dams in future years as a consequence of changing climate
2010 | 2020s | 2050s | 2080s | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Area (sq. km) | Population in the region | No. dams (%) | No. people within 5 km from reservoirs | Area (sq. km) | Population in the region | No. dams | No. people within 5 km from reservoirs | Area (sq. km) | Population in the region | No. dams (%) | No. people within 5 km from reservoirs | Area (sq. km) | Population in the region | No. dams (%) | No. people within 5 km from reservoirs | |
RCP 2.6 | ||||||||||||||||
Stable | 7,086,268 | 298,682,666 | 307 (24) | 6,406,226 | 7,408,321 | 361,264,297 | 354 (28) | 7,198,341 | 8,264,718 | 489,811,003 | 377 (30) | 8,872,392 | 9,113,482 | 546,622,885 | 386 (30) | 10,097,454 |
Unstable | 14,459,409 | 418,451,433 | 416 (33) | 8,193,239 | 14,378,791 | 462,113,462 | 433 (34) | 9,202,466 | 13,666,490 | 590,443,015 | 645 (51) | 12,105,161 | 12,972,969 | 682,788,932 | 628 (50) | 14,713,709 |
No malaria | 2,042,223 | 273,355,662 | 545 (43) | 5,605,474 | 1,800,788 | 322,401,006 | 481 (38) | 4,891,743 | 1,656,692 | 281,714,037 | 246 (19) | 4,048,543 | 1,501,449 | 319,587,199 | 254 (20) | 3,310,021 |
Total | 23,587,900 | 990,489,781 | 1268 (100) | 20,204,939 | 23,587,900 | 1,145,778,765 | 1268 (100 | 21,292,550 | 23,587,900 | 1,361,968,055 | 1268 (100 | 25,026,096 | 23,587,900 | 1,548,999,016 | 1268 (100) | 28,121,184 |
RCP 8.5 | ||||||||||||||||
Stable | 7,086,268 | 298,682,666 | 307 (24) | 6,406,226 | 7,871,237 | 403,671,332 | 381 (30) | 8,671,114 | 8,671,114 | 498,594,276 | 346 (27) | 9,408,302 | 10,945,711 | 572,083,572 | 427 (34) | 10,983,666 |
Unstable | 14,459,409 | 418,451,433 | 416 (33) | 8,193,239 | 13,950,337 | 501,242,107 | 609 (48) | 10,309,672 | 10,309,672 | 621,144,735 | 692 (55) | 13,611,448 | 11,511,801 | 697,130,875 | 645 (51) | 15,231,541 |
No malaria | 2,042,223 | 273,355,662 | 545 (43) | 5,605,474 | 1,766,326 | 388,923,354 | 268 (21) | 3,833,107 | 3,833,107 | 349,366,669 | 230 (18) | 3,115,432 | 1,130,388 | 381,136,413 | 196 (15) | 3,109,886 |
Total | 23,587,900 | 990,489,781 | 1268 (100) | 20,204,939 | 23,587,900 | 1,293,836,793 | 1268 (100) | 22,813,893 | 23,587,900 | 1,469,105,680 | 1268 (100) | 26,135,182 | 23,587,900 | 1,650,350,860 | 1268 (100) | 29,325,093 |
Estimated future population at risk of malaria around dams in SSA
Estimated malaria incidence around dams in future climate in SSA
Annual malaria cases associated with dams in the future
Climate scenario/malaria stability | 2010 | 2020s | 2050s | 2080s | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Number malaria cases <5 km | Number malaria cases attributable to presence of dams | Number malaria cases <5 km | Number malaria cases (assuming similar case rate as >5 km) | Number malaria cases attributable to presence of dams | Number malaria cases <5 km | Number malaria cases (assuming similar case rate as >5 km) | Number malaria cases attributable to presence of dams | Number malaria cases <5 km | Number malaria cases (assuming similar case rate as >5 km) | Number malaria cases attributable to presence of dams | |
RCP 2.6 | |||||||||||
Stable | 1,337,979 | 203,718 | 2,221,953 | 1,794,093 | 427,860 | 3,008,238 | 2,369,683 | 638,555 | 3,763,321 | 3,006,427 | 718,070 |
Unstable | 1,337,956 | 919,281 | 1,204,302 | 416,290 | 788,012 | 2,402,874 | 937,677 | 1,465,197 | 3,052,593 | 1,660,640 | 1,656,318 |
Total | 2,675,935 | 1,122,999 | 3,426,255 | 2,210,383 | 1,215,872 | 5,411,112 | 2,307,360 | 2,103,752 | 6,815,914 | 5,067,067 | 2,374,388 |
RCP 8.5 | |||||||||||
Stable | 1,337,979 | 203,718 | 2,507,720 | 1,905,353 | 602,367 | 3,162,273 | 2,312,261 | 850,013 | 4,007,444 | 3,406,427 | 601,017 |
Unstable | 1,337,956 | 919,281 | 1,624,363 | 535,513 | 1,088,850 | 4,051,684 | 1,919,967 | 2,131,717 | 4,976,346 | 2,606,657 | 2,369,689 |
Total | 2,675,935 | 1,122,999 | 4,132,083 | 2,520,866 | 1,611,217 | 7,213,957 | 4,232,228 | 2,981,730 | 8,983,790 | 6,013,084 | 2,970,706 |
Impacts of population growth
2020s | 2050s | 2080s | |||||||
---|---|---|---|---|---|---|---|---|---|
Additional malaria cases due to population increase (%)a
| Additional malaria cases due to climate change (%) | Total additional malaria cases due to population increase and climate change | Additional malaria cases due to population increase (%) | Additional malaria cases due to climate change (%) | Total additional malaria cases due to population increase and climate change | Additional malaria cases due to population increase (%) | Additional malaria cases due to climate change (%) | Total additional malaria cases due to population increase and climate change | |
RCP 2.6 | |||||||||
Stable | 205,158 (42) | 281,234 (58) | 486,392 | 638,737 (57) | 491,522 (43) | 1,130,259 | 956,028 (40) | 1,429,314 (60) | 2,385,342 |
Unstable | 118,080 (46) | 136,618 (54) | 254,698 | 457,695 (43) | 607,223 (57) | 1,064,918 | 762,895 (44) | 951,742 (56) | 1,714,637 |
Total | 323,238 (41) | 457,851 (59) | 781,089 | 1,096,432 (50) | 1,098,745 (50) | 2,195,177 | 1,718,923 (42) | 2,381,056 (58) | 4,099,979 |
RCP 8.5 | |||||||||
Stable | 586,606 (61) | 373,335 (39) | 959,941 | 777,538 (43) | 1,046,756 (57) | 1,824,294 | 1,185,557 (44) | 1,483,908 (56) | 2,669,465 |
Unstable | 147,623 (43) | 198,784 (57) | 346,407 | 633,930 (28) | 1,634,556 (72) | 2,268,486 | 823,481 (27) | 2,200,442 (73) | 3,023,923 |
Total | 834,229 (59) | 572,119 (41) | 1,406,348 | 1,411,468 (34) | 2,681,312 (66) | 4,092,780 | 2,009,038 (35) | 3,684,350 (65) | 5,693,388 |