---
attributes: ~
caption: 'Ragweed pollen season length has increased in central North America between 1995 and 2011 by as much as 11 to 27 days in parts of the U.S. and Canada in response to rising temperatures. Increases in the length of this allergenic pollen season are correlated with increases in the number of days before the first frost. As shown in the figure, the largest increases have been observed in northern cities. (Data updated from Ziska et al. 2011<tbib>2d1ffd71-6c31-4d2e-9867-bdf330be45c1</tbib>; Photo credit: Lewis Ziska, USDA).'
chapter:
  description: ~
  display_name: 'Chapter 9: Human Health'
  doi: 10.7930/J0PN93H5
  identifier: human-health
  number: 9
  report_identifier: nca3
  sort_key: 90
  title: Human Health
  url: http://nca2014.globalchange.gov/report/sectors/human-health
chapter_identifier: human-health
cited_by: []
contributors: []
create_dt: ~
description: 'Ragweed pollen season length has increased in central North America between 1995 and 2011 by as much as 11 to 27 days in parts of the U.S. and Canada in response to rising temperatures. Increases in the length of this allergenic pollen season are correlated with increases in the number of days before the first frost. As shown in the figure, the largest increases have been observed in northern cities. (Data updated from Ziska et al. 2011<tbib>2d1ffd71-6c31-4d2e-9867-bdf330be45c1</tbib>; Photo credit: Lewis Ziska, USDA).'
display_name: '9.2: Ragweed Pollen Season Lengthens'
files:
  - display_name: health_ragweed_pollen_season_V4.png
    file: 55/1c/a053c25df73108cdc11bd1d0cf1c/health_ragweed_pollen_season_V4.png
    href: http://data.globalchange.gov/assets/55/1c/a053c25df73108cdc11bd1d0cf1c/health_ragweed_pollen_season_V4.png
    identifier: 28596ccd-8bc0-473d-97ee-ec425e7caebf
    landing_page: ~
    location: ~
    mime_type: image/png
    sha1: a0d9972de0fe37d3563d07d58067041ec2706aa8
    size: 586019
    thumbnail: 55/1c/a053c25df73108cdc11bd1d0cf1c/.thumb-28596ccd-8bc0-473d-97ee-ec425e7caebf.png
    thumbnail_href: http://data.globalchange.gov/assets/55/1c/a053c25df73108cdc11bd1d0cf1c/.thumb-28596ccd-8bc0-473d-97ee-ec425e7caebf.png
    type: file
    uri: /file/28596ccd-8bc0-473d-97ee-ec425e7caebf
    url: http://data.globalchange.gov/assets/55/1c/a053c25df73108cdc11bd1d0cf1c/health_ragweed_pollen_season_V4.png
href: http://52.38.26.42:8080/report/nca3/chapter/human-health/figure/ragweed-pollen-season-lengthens.yaml
identifier: ragweed-pollen-season-lengthens
kindred_figures: []
lat_max: ~
lat_min: ~
lon_max: ~
lon_min: ~
ordinal: 2
parents: []
references:
  - href: http://52.38.26.42:8080/reference/2d1ffd71-6c31-4d2e-9867-bdf330be45c1.yaml
    uri: /reference/2d1ffd71-6c31-4d2e-9867-bdf330be45c1
report:
  display_name: 'Climate Change Impacts in the United States: The Third National Climate Assessment'
report_identifier: nca3
source_citation: ~
submission_dt: ~
time_end: ~
time_start: ~
title: Ragweed Pollen Season Lengthens
type: figure
uri: /report/nca3/chapter/human-health/figure/ragweed-pollen-season-lengthens
url: http://nca2014.globalchange.gov/highlights/report-findings/human-health/graphics/ragweed-pollen-season-lengthens
usage_limits: Copyright protected. Obtain permission from the original figure source.