Ocean surface temperatures hit a record high in July, reaching 61 degrees, or 1.06 degrees warmer than the 20th century average.

Scientists at the National Oceanic and Atmospheric Administration's Climate Data Center said part of the increase was attributed to an El Nino in the Pacific, but other factors such as the continued melting of the Arctic ice cap, which in July was its third smallest size on record.

In September, Congress may also heat up as pressure builds on the the Senate to pass climate change legislation in the wake of action by the House.

In late June, the Democratic-controlled House narrowly passed sweeping legislation that calls for the nation's first limits on pollution linked to global warming and aims to usher in a new era of cleaner, yet more costly energy.

The vote was 219-212, capping months of negotiations and days of intense bargaining among Democrats. Republicans were overwhelmingly against the measure-only eight voted in favor-arguing it would destroy jobs in the midst of a recession while burdening consumers with a new tax in the form of higher energy costs.

The legislation would require the United States to reduce carbon dioxide and other greenhouse gas emissions by 17 percent from 2005 levels by 2020 and by about 80 percent by midcentury. That was slightly more aggressive than President Obama originally wanted, 14 percent by 2020 and the same 80 percent by midcentury.

Polluters would be required to buy credits to offset excessive emissions. Credits could be created by reductions at another facility, or from actions such as a farmer planting carbon dioxide-absorbing trees on his land.

U.S. carbon dioxide emissions from the burning of fossil fuels are rising at about 1 percent a year and are predicted to continue increasing without mandatory limits.

Chesapeake Bay Foundation President William Baker called the House passage "a huge victory" and said that "efforts to reduce carbon dioxide emissions will also help reduce nitrogen pollution, the leading cause of the dead zones and harmful algal blooms that are damaging the Chesapeake Bay."

Baker said the legislation would encourage farmers in this region to take actions that not only reduce nutrient pollution but also generate carbon credits, such as planting forest stream buffers.

The bill could also provide a direct financial benefit to Bay efforts, as it creates a fund to help regions take action that help natural resources adapt to the impacts of climate change. A similar provision has been proposed for a yet-to-be released Senate bill.

Climate change could dramatically alter the Bay region and make cleanup efforts much more difficult. It's likely, for instance, that storms would become more intense, which would drive more nutrients and sediment into waterways and overwhelm many of the runoff control practices now in use.

"We can't restore the Bay unless we deal with climate change," said Hilary Harp Falk, director of the new Chesapeake Bay Watershed Coalition. The recently formed coalition is a network of more than 60 organizations within the watershed that have come together to push for legislative actions that promote clean water.

"This is one of our top issues for 2009," she said. "A lot of the coalition members in individual states are already working very hard on this issue."

Senate Environment and Public Works Chairwoman Barbara Boxer plans to unveil a global warming bill on Sept. 8, the day after Congress returns from its summer break.

Congressional leaders and Obama administration officials have said they would like to pass climate change legislation this fall.

Climate Change & The Bay

Climate change could dramatically alter the Bay ecosystem. Some of the consequences scientists say are likely for the Bay in coming years include:

  • The frequency of harmful algae blooms could increase as warming conditions and higher levels of carbon dioxide in the atmosphere create conditions that promote their growth.
  • Winter and spring precipitation is likely to increase, washing more nutrients into the Bay and magnifying the size of its oxygen-starved "dead zone." That would be compounded because water also holds less oxygen as it warms.
  • Eelgrass, the dominant seagrass in the lower Bay, will decline and possibly disappear because of its low tolerance to warm temperatures.
  • Changes in Bay salinity and temperature would likely create conditions that make the Bay more conducive to invasive species.
  • Warmer water temperatures and increased nutrients could increase the abundance of pathogenic bacteria that cause diseases in fish, shellfish and humans.
  • Increased carbon dioxide levels in the atmosphere would make Bay water more acidic, like ocean water. Among the consequences would be thinner oyster and clam shells.
  • Chesapeake water levels, already rising faster than the global average, will further accelerate, increasing coastal flooding, speeding coastal erosion and submerging tidal wetlands.