Hawaii needs to prepare for diminishing supplies of freshwater, dying coral reefs, stronger storms, rising sea levels and fewer native species, according to the third U.S. National Climate Assessment, a comprehensive report on the long-term effects of climate change on regions throughout the country.

The section on Hawaii, which was written by top local scientists, is similar to a draft of the report released last year, but has a sharper focus, according to John Marra, one of the report’s lead authors and a climate change expert at the National Oceanic and Atmospheric Administration.

The report is being hailed by local officials — and the White House — as a wake-up call about the importance of cutting carbon dioxide emissions, switching to renewable energy sources and accelerating plans to adapt to climate change.

The “report is a harsh reality check for anyone who thinks we don’t need to act on climate change,” U.S. Sen. Brian Schatz said in a press release. “Rising ocean temperatures and sea levels have and will continue to threaten Hawaii’s food and water security, unless we act now.”

Gov. Neil Abercrombie also issued a statement warning that Hawaii, as an island-state, is “especially vulnerable to climate change.”

The 800-page report is a key part of President Barack Obama’s Climate Action Plan, the administration’s sweeping policy for reducing greenhouse gas emissions. It was compiled by a team of more than 300 scientists and other experts from government, academia and the private sector, and vetted by the National Academy of Sciences.

Nationally, the report warns that Americans already feel the effects of a warming climate.

“Summers are longer and hotter, and extended periods of unusual heat last longer than any living American has ever experienced,” according to the report. “Winters are generally shorter and warmer. Rain comes in heavy downpours. People are seeing changes in the length and severity of seasonal allergies, the plant varieties that thrive in their gardens, and the kinds of birds they see in any particular month in their neighborhoods.”

Other changes are more dramatic. The report points to more flooding streets in coastal areas, an increase in wildfires in the western part of the country and melting Arctic ice that is disappearing faster than earlier projections.

Nationally, the average temperature has risen by as much as 1.9 degrees Fahrenheit since 1895. The majority of the increase took place in the last four decades, according to the report.

By the end of this century, the temperature could rise as much as 5 more degrees — even if greenhouse gas emissions are curtailed. Without any check on rising emissions, the temperature could increase by as much as 10 degrees, the report warns.

In Hawaii, some of the worst effects are in the ocean around the islands where water temperatures are rising and increased atmospheric carbon dioxide emissions are causing the ocean to acidify.

The changes are causing disease outbreaks and major bleaching episodes that damage and kill coral, and threaten both reef fish and deep-water species, including important tuna stocks, according to the report.

“These changes to both coral and fish pose threats to communities, cultures, and ecosystems of the Pacific Islands both directly through their impact on food security and indirectly through their impact on economic sectors including fisheries and tourism,” according to the report.

The rate of sea level rise has doubled in the past two decades and, during the past century, the sea rose by 8 inches, according to the report. By the end of this century, it could rise another one to four feet.

For Hawaii, this means homes, hotels, roads, and other infrastructure built close to the coastlines are under threat.

In Hawaii, where tourism makes up one-fourth of the state’s economy and is the largest economic driver, damage to coastal areas could be devastating.

The “loss of Waikiki alone could lead to an annual loss of $2 billion in visitor expenditures,” according to the report.

Sea level rise and flooding are also expected to overwhelm sewer systems in the coming decades.

Hawaii’s harbors and airports are also at risk, which means the state’s energy and food security are too. “Because Pacific Islands are almost entirely dependent upon imported food, fuel, and material, the vulnerability of ports and airports to extreme events, sea level rise, and increasing wave heights is of great concern,” according to the report.

On land, the quantity of freshwater is expected to decline throughout the century, limiting drinking water supplies and the ability of farmers to irrigate their fields.

Drought-like conditions on the islands’ upper slopes will mean that less rainfall will make it into watersheds. Meanwhile, rising sea levels are expected to lead to saltwater contamination of underground water resources.

Native plants and animals are also expected to endure increasing stress because of rising temperatures and, in some areas, reduced rainfall. Plants that live solely in high-elevation ecosystems, such as Haleakala’s silversword — which exists nowhere else on earth — will be at particular risk of extinction.

Native forest birds are also expected to be increasingly susceptible to mosquitoes that carry diseases, such as avian malaria. Humans could also endure more cases of dengue fever.

Movements of people fleeing immediate effects of climate change could also spell trouble. Hawaii could see an influx of immigrants from lower-lying islands where rising seas may submerge inhabitable land.

While many of the reports findings aren’t new, the latest report is perhaps the most comprehensive assessment of the effects of climate change around the country and it is meant to form a basis for long-term planning efforts.

In Hawaii, state agencies have already drafted a framework for adapting to climate change, according to the report. Global warming is also factored into Hawaii’s plan to mitigate hazards for the U.S. Federal Emergency Management Agency.

About the Author