WASHINGTON — President Barack Obama sent Congress his final budget on Tuesday, proposing to spend a record $4.1 trillion on a number of initiatives, from a new war on cancer to combating global warming to fighting growing threats from Islamic State militants.

The spending plan, for the budget year that begins Oct. 1 — just 3½ months before he leaves office, is facing heavy fire from Republicans who hope to capture the White House. The proposal has dim prospects of winning approval in a GOP-controlled Congress.

In all, Obama’s budget would increase taxes by $2.6 trillion over the coming decade, nearly double the $1.4 trillion in new taxes Obama sought and failed to achieve in last year’s budget.

In an election year, Obama’s budget is filled with ideas sure to appeal to Democrats: A “moonshot” initiative to cure cancer; increasing Pell Grants for college students from low-income backgrounds; renewed incentives for GOP-governed states to join the expanded Medicaid system established under the health care law, and incentives to boost individual retirement accounts.

“The budget that we are releasing today reflects my priorities and the priorities I believe will help advance security and prosperity for America for many years to come,” Obama told reporters after a White House meeting.

GOP lawmakers said Obama’s proposal to impose a $10-per-barrel tax on crude oil to bring in an additional $319 billion over the next decade had no chance of congressional approval. Obama’s budget would use that extra money to fund billions of dollars in alternative transportation programs as part of the president’s efforts to deal with global warming.

“President Obama will leave office having never proposed a budget that balances — ever. This isn’t even a budget so much as it is a progressive manual for growing the federal government at the expense of hardworking Americans,” said House Speaker Paul Ryan, R-Wis.

While Republicans insisted Obama’s budget was dead on arrival, White House officials expressed hope they could obtain bipartisan support for a number of Obama’s initiatives such as the effort to combat heroin and opioid addiction.

Even with the increased taxes, Obama’s budget projects sharply higher deficits in coming years, totaling $9.8 trillion over the next decade. Just last summer, Obama’s baseline forecast a deficit of $8 trillion over the next decade.

Much of the problem stems from the surge in spending on the government’s big benefit programs of Social Security and Medicare, which are forecast to soar with the retirement of millions of baby boomers.

The budget sees the economy growing at a 2.6 percent rate this year, though administration officials noted that projection was finalized in November, prior to the recent stock market slide. Inflation would remain low, registering a 1.5 percent gain this year.

Obama’s new budget projects a deficit for the current 2016 budget year of $616 billion, sharply higher than the latest forecast by the Congressional Budget Office that this year’s deficit would total $544 billion.

Both projections are above the actual deficit of $438 billion recorded last year, the lowest deficit total for Obama’s presidency, a period when the deficits soared to above $1 trillion annually for four years as the government was buffeted by the worst recession in seven decades and a serious financial crisis.

Republicans have long complained that Obama has failed to attack the chief cause of future deficits, the soaring cost of entitlements. Previous Obama budgets did propose such things as slowing the automatic inflation increase for Social Security. But Obama abandoned those proposals when it became clear that Republicans were opposed to his suggestions to raise taxes on the wealthy as a way to reduce the size of the necessary benefit cuts.

House Ways and Means Chairman Kevin Brady, R-Texas, said the budget “is clearly about promoting his liberal legacy instead of securing America’s financial future.”

The budget also pledges to make Americans safer in an increasingly dangerous world through higher military spending to fight the Islamic State terrorist threat and increased support for cybersecurity in the wake of last summer’s hack of government computers that compromised the personal information of 21 million Americans.

The administration’s budget asks for a $19 billion increase in spending to upgrade cybersecurity across government agencies, including $3 billion for an overhaul of federal computer systems.

The administration seeks to bolster funds for the Securities and Exchange Commission and the Commodity Futures Trading Commission, Wall Street regulators struggling to meet their heightened responsibilities following the 2008 financial crisis. The additional money would be used to fill obvious gaps in the agencies’ oversight of investment advisers and clearinghouses for financial products, the administration says.

Separately, Obama has proposed $1.8 billion to combat the Zika virus, asking for the money immediately as emergency spending on top of the $1.1 trillion catchall spending bill that passed in December. The new budget also seeks to boost funding to deal with the water crisis in Flint, Mich., by increasing funding for the Environmental Protection Agency’s state drinking water fund by $158 million.

But Sen. Ben Cardin, D-Md., objected that Obama would get that increase by transferring funds from a separate state clean water fund.

AP reporters Alan Fram, Tami Abdollah, Jeff Horwitz and Josh Lederman contributed to this report.