WARSAW (AP) ― U.N. climate talks head into a tense final week Monday after the diplomatic effort to reduce global warming gases was hit by a series of setbacks, including Japan’s decision to ditch its voluntary emissions target.

The two-decade-old negotiations have so far failed to achieve their goal of slashing emissions of CO2 and other greenhouse gases that scientists say are warming the planet. They don’t seem to be getting any closer after a tumultuous first week at this year’s session in Warsaw.

Despite a tearful call for action from a delegate from the typhoon-ravaged Philippines, no major carbon polluter raised their pledges to cut emissions.

Instead, Australia’s conservative government fulfilled a campaign promise and introduced a bill to scrap the country’s carbon tax, while Japan drastically scaled back its emissions target.

The moves drew criticism from developing countries who say the world’s rich countries have a historical responsibility for climate change and should take the lead in fighting it.

“We need to be very concerned with individual actions of developed countries that are backtracking (on) their commitments,” said Brazilian negotiator Jose Marcondes de Carvalho.

Most Australian economists agree that the country cannot achieve its voluntary target of reducing emissions by 5 percent by 2020 without industry paying a price on carbon.

Japan said its initial target of reducing emissions by 25 percent from 1990 levels was unrealistic. Following the 2011 accident at the Fukushima Dai-ichi nuclear power plant, Japan shut all its nuclear plants for safety checks and had to shift back to power coming from coal, oil and gas, all of which are heavy on CO2 emissions. Japan’s new target represents a 3 percent increase over 1990 emissions.

Brazil, too, delivered bad news at the talks when it reported that annual destruction of its Amazon rainforest jumped by 28 percent after four straight years of declines.

Scientists say that the main ways that humans are affecting the climate system is through the CO2 emissions from burning fossil fuels and deforestation.

Though no major decisions are on the agenda in Warsaw, the talks are meant to pave the way for a bigger global climate treaty in 2015. Environmental groups watching the first week of talks were discouraged.

“After one week, the world governments continue to disappoint their citizens who are fighting against catastrophic climate change and its devastating impacts,” said Martin Kaiser of Greenpeace.

Climate activists are expected to stage protests Monday when a high-profile coal industry summit kicks off at Poland’s Economy Ministry. Coal is a major contributor to CO2 emissions and activists are outraged that coal-reliant Poland is presiding over the coal event at the same time as the U.N. climate conference.

Several U.N. reports have warned that the world is running out of time to rein in emissions enough to avoid the most dangerous effects of warming. Still, the talks have been bogged down by disputes between rich and poor countries over emissions cuts and climate aid to help poor countries convert to cleaner energy sources and adapt to a shifting climate.

Pointing to the typhoon damage in the Philippines, small island states and other vulnerable nations are also asking for a mechanism for compensation for the damage resulting from climate impacts such as rising seas.