אילו ערים ישקעו כשהטמפרטורה העולמית תעלה ב-2 מעלות?

פורסם: 15 בנוב׳ 2015, 10:03 על ידי: Sustainability Org   [ עודכן 15 בנוב׳ 2015, 12:31 ]

מחקר: עלייה של 2 מעלות צלזיוס בטמפרטורה העולמית תביא לשקיעת ערים, ובהן ניו-יורק, שנחאי ומומבאי, שמאכלסות כיום כ-280 מיליון בני אדם ■ החדשות הטובות: זה יקרה בעוד מאות שנים, אולי אפילו 2,000 שנים

שירות גלובס, 9/11/15

עלייה של 2 מעלות צלזיוס בטמפרטורה העולמית תביא לשקיעת ערים, ובהן ניו-יורק, שנחאי ומומבאי, שמאכלסות כיום כ-280 מיליון בני אדם ברחבי העולם - כך עולה ממחקר חדש שפרסמה חברת המחקר האמריקאית Climate Central.

לפי המחקר, עלייה של 4 מעלות צלזיוס בטמפרטורה העולמית - המסלול העגום שבו צועד העולם כיום - תוביל לשקיעת ריכוזי אוכלוסין של יותר מ-600 מיליון בני אדם.

לכתבה בגלובס



Mapping Choices: Carbon, Climate, and Rising Seas — Our Global Legacy

Description: This report assesses and lists global nations and urban agglomerations at risk by projected total population exposure, percent exposure, and differences in exposure to locked-in long-term sea level rise under warming scenarios.

Date: November 2015


Full PDF of Report | Click here to download city and national data from the analysis >>


Executive Summary

Carbon emissions causing 4 degrees Celsius of warming (7.2 degrees Fahrenheit) — a business-as- usual scenario — could lock in enough eventual sea level rise to submerge land currently home to 470 to 760 million people globally. Carbon cuts resulting in the proposed international target of 2 °C warming (3.6 °F) would reduce the rise locked in so that it would threaten areas now occupied by as few as 130 million people. This contrast is one expression of what is at stake in the December 2015 global climate talks in Paris.

This report builds closely on a paper first published online in October 2015 in the Proceedings of the National Academy of Sciences of the United States of America by the same authors. That research used relationships between cumulative carbon emissions, warming, and the future global sea level rise they lock in to assess implications for the United States and its cities. What distinguishes the current report is its application of sea level projections to global elevation, tidal, population, and administrative boundary data, instead of U.S. data only.

Among all nations, this report finds that China has the most to lose from business as usual, with 145 million citizens today on implicated land. China also has the most to gain from limiting warming to 2 °C, which would cut the total to 64 million. Twelve other nations have more than 10 million people living on implicated land under 4 °C warming — India, Bangladesh, Viet Nam, Indonesia, Japan, the United States, Philippines, Egypt, Brazil, Thailand, Myanmar, and the Netherlands, in descending order of total threats. A carbon path that limits warming to 2 °C would reduce exposure by more than 10 million in each listed nation except the last two, and by half or more in all listed nations but Viet Nam (still achieving 44% reduction), Brazil (45%) and the Netherlands (13%). Global megacities with the top ten populations in the balance include Shanghai, Hong Kong, Calcutta, Mumbai, Dhaka, Jakarta, and Hanoi. 4 °C warming could lead to submergence of land inhabited by more than half the population of Shanghai, Mumbai and Hanoi, among these.

These results are based on median sea level rise projections. They are also based on global elevation data with a tendency to understate exposure.

Carbon emissions this century can lock in these projected threats, but the associated sea level rise is expected to play out over a longer period, likely centuries.

This report assesses and lists global nations and urban agglomerations at risk by projected total population exposure, percent exposure, and differences in exposure under warming scenarios of 1.5, 2, 3 and 4 °C (2.7, 3.6, 5.4 and 7.2 °F). Results do not account for present or future shoreline defenses, such as levees, that might be built, nor for future population growth, decline or relocation.

In conjunction with this report, Climate Central has extended its interactive and embeddable Mapping Choices platform globally (choices.climatecentral.org). Users can now type in any coastal city name or postal code worldwide, and visually compare the potential consequences of different warming or emissions scenarios on a local map. Climate Central is also serving Google Earth layers for visualizing sea levels associated with 2 °C or 4 °C warming in areas with 3-D building data, available here; and offering spreadsheets for download with analytic results for comprehensive lists of global nations and coastal urban agglomerations, available here

- See more at: http://sealevel.climatecentral.org/research/reports/mapping-choices-carbon-climate-and-rising-seas-our-global-legacy#sthash.R1Xl776F.dpuf



The Facts About Sea Level Rise

Global warming has raised global sea level about 8 inches since 1880, and the rate of rise is accelerating. Rising seas dramatically increase the odds of damaging floods from storm surges. A Climate Central analysis finds the odds of “century” or worse floods occurring by 2030 are on track to double or more, over widespread areas of the U.S. These increases threaten an enormous amount of damage. Across the country, nearly 5 million people live in 2.6 million homes at less than 4 feet above high tide — a level lower than the century flood line for most locations analyzed. And compounding this risk, scientists expect roughly 2 to 7 more feet of sea level rise this century — a lot depending upon how much more heat-trapping pollution humanity puts into the sky.

Explore

Search or navigate our interactive tools above to see maps of areas below different amounts of sea level rise and flooding, down to neighborhood scale, matched with area timelines of risk. The tool also provides statistics of population, homes and land affected by city, county and state, plus links to factsheets, data downloads, action plans, embeddable widgets, and more.

- See more at: http://sealevel.climatecentral.org/#sthash.HcPY5sxO.dpuf


‘Risk Zone’ Map Redesigned and Expanded Globally

November 8, 2015

By Climate Central

Climate Central has launched a redesigned version of its Surging Seas Risk Zone Map, and extended the map from U.S.-only to global coverage. Our goal is to provide a powerful new web tool to boost global understanding and communication of sea level rise and coastal flooding under different carbon emissions scenarios, and to better inform coastal planning and resilience efforts globally.  

New Risk Zone Map features include:

  • Ability to explore inundation ​risk ​up to 30 meters (100 feet) high across the world's coastlines

  • Local sea level rise projections at over 1,000 tide gauges on 6 continents displayed on the map

  • Flood risk projections included at select tide gauges within the United States

  • Customized map image downloads via camera icon at top right of screen

The map is embeddable and searchable by city, state, postal code, and other location names. Map areas below the selected water level are displayed as satellite imagery shaded in blue indicating vulnerability to flooding from combined sea level rise, storm surge, and tides, or to permanent submergence by long-term sea level rise. Map areas above the selected water level are shown in map style using white and pale grays.

For map areas in the U.S., the Risk Zone Map incorporates high-resolution, high-accuracy lidar elevation data supplied by NOAA, displays points of interest, and contains layers displaying social vulnerability, population density, ethnicity, income, and property value. For map areas outside the United States, very little lidar data is available. Instead, we use radar satellite-based data collected from NASA’s Shuttle Radar Topography Mission (SRTM). This elevation data covers nearly the entire populated world, but is less accurate than lidar. SRTM’s pixel resolution is lower, and in areas of dense urban development and vegetation, SRTM tends to overestimate elevation. Recent work also suggests that SRTM usually underpredicts exposure from sea level rise and coastal flooding. Outside the U.S., our flood maps should therefore be seen as likely lower bounds on the extent of potential inundation for each water level.

Surging Seas Risk Zone Map and our companion Risk Finder are listed as resources on these national tool portals: U.S. Climate Resilience Toolkit, NOAA Digital Coast, The White House Climate Data Initiative, EPA My Environment.

This effort is made possible thanks to the many organizations that have supported Climate Central and its sea level program, including the Kresge, Schmidt Family, and V. Kann Rasmussen Foundations. Map development was also supported in part by U.S. National Science Foundation grant ARC-1203415. We further appreciate Stamen Design, the interactive mapping experts with whom we have worked closely from the very start of all of our sea level mapping.



Related tools: Surging Seas Risk Zone Map, Surging Seas Risk Finder

Related pages: Science Behind the Tool, FAQs

- See more at: http://sealevel.climatecentral.org/news/risk-zone-map-redesigned-and-expanded-globally#sthash.CfPAQZLj.dpuf

Related articles:

Comments